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    <link:label id="lab_us-gaap_SegmentGeographicalGroupsOfCountriesGroupOneMember_55CF520615F215B5EA4F1626706FAB7E_label_en-US" xlink:label="lab_us-gaap_SegmentGeographicalGroupsOfCountriesGroupOneMember_55CF520615F215B5EA4F1626706FAB7E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Segment, Geographical, Groups of Countries, Group One [Member]</link:label>
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    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SegmentGeographicalGroupsOfCountriesGroupOneMember_55CF520615F215B5EA4F1626706FAB7E" xlink:to="lab_us-gaap_SegmentGeographicalGroupsOfCountriesGroupOneMember_55CF520615F215B5EA4F1626706FAB7E" xlink:type="arc" />
    <link:label id="lab_biib_SegmentGeographicalGroupsOfCountriesGroupOtherMember_69D0E25C00EDDCE8517D1626706F7F7E_verboseLabel_en-US" xlink:label="lab_biib_SegmentGeographicalGroupsOfCountriesGroupOtherMember_69D0E25C00EDDCE8517D1626706F7F7E" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Other [Member]</link:label>
    <link:label id="lab_biib_SegmentGeographicalGroupsOfCountriesGroupOtherMember_69D0E25C00EDDCE8517D1626706F7F7E_label_en-US" xlink:label="lab_biib_SegmentGeographicalGroupsOfCountriesGroupOtherMember_69D0E25C00EDDCE8517D1626706F7F7E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Segment Geographical Groups Of Countries Group Other [Member]</link:label>
    <link:label id="lab_biib_SegmentGeographicalGroupsOfCountriesGroupOtherMember_69D0E25C00EDDCE8517D1626706F7F7E_documentation_en-US" xlink:label="lab_biib_SegmentGeographicalGroupsOfCountriesGroupOtherMember_69D0E25C00EDDCE8517D1626706F7F7E" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Segment geographical groups of countries group other.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_SegmentGeographicalGroupsOfCountriesGroupOtherMember" xlink:label="loc_biib_SegmentGeographicalGroupsOfCountriesGroupOtherMember_69D0E25C00EDDCE8517D1626706F7F7E" xlink:type="locator" />
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    <link:label id="lab_country_DE_364EF5674D877AD3642A1626706FB776_verboseLabel_en-US" xlink:label="lab_country_DE_364EF5674D877AD3642A1626706FB776" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Germany [Member]</link:label>
    <link:label id="lab_country_DE_364EF5674D877AD3642A1626706FB776_label_en-US" xlink:label="lab_country_DE_364EF5674D877AD3642A1626706FB776" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">GERMANY</link:label>
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    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_country_DE_364EF5674D877AD3642A1626706FB776" xlink:to="lab_country_DE_364EF5674D877AD3642A1626706FB776" xlink:type="arc" />
    <link:label id="lab_us-gaap_EntityWideRevenueMajorCustomerLineItems_3DAE901910427107F7ED1626706F6783_terseLabel_en-US" xlink:label="lab_us-gaap_EntityWideRevenueMajorCustomerLineItems_3DAE901910427107F7ED1626706F6783" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Revenue, Major Customer [Line Items]</link:label>
    <link:label id="lab_us-gaap_EntityWideRevenueMajorCustomerLineItems_3DAE901910427107F7ED1626706F6783_label_en-US" xlink:label="lab_us-gaap_EntityWideRevenueMajorCustomerLineItems_3DAE901910427107F7ED1626706F6783" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenue, Major Customer [Line Items]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EntityWideRevenueMajorCustomerLineItems" xlink:label="loc_us-gaap_EntityWideRevenueMajorCustomerLineItems_3DAE901910427107F7ED1626706F6783" xlink:type="locator" />
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    <link:label id="lab_us-gaap_SegmentsGeographicalAreasAbstract_969984F8CC523C2170FB1626706F4C5E_verboseLabel_en-US" xlink:label="lab_us-gaap_SegmentsGeographicalAreasAbstract_969984F8CC523C2170FB1626706F4C5E" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Geographic information</link:label>
    <link:label id="lab_us-gaap_SegmentsGeographicalAreasAbstract_969984F8CC523C2170FB1626706F4C5E_label_en-US" xlink:label="lab_us-gaap_SegmentsGeographicalAreasAbstract_969984F8CC523C2170FB1626706F4C5E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Segments, Geographical Areas [Abstract]</link:label>
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    <link:label id="lab_biib_RevenuesFromUnconsolidatedJointBusiness_9C59F67BF3D978409ABC1626706F9FF6_verboseLabel_en-US" xlink:label="lab_biib_RevenuesFromUnconsolidatedJointBusiness_9C59F67BF3D978409ABC1626706F9FF6" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Revenues from unconsolidated joint business</link:label>
    <link:label id="lab_biib_RevenuesFromUnconsolidatedJointBusiness_9C59F67BF3D978409ABC1626706F9FF6_label_en-US" xlink:label="lab_biib_RevenuesFromUnconsolidatedJointBusiness_9C59F67BF3D978409ABC1626706F9FF6" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenues From Unconsolidated Joint Business</link:label>
    <link:label id="lab_biib_RevenuesFromUnconsolidatedJointBusiness_9C59F67BF3D978409ABC1626706F9FF6_documentation_en-US" xlink:label="lab_biib_RevenuesFromUnconsolidatedJointBusiness_9C59F67BF3D978409ABC1626706F9FF6" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Revenues from unconsolidated joint business.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_RevenuesFromUnconsolidatedJointBusiness" xlink:label="loc_biib_RevenuesFromUnconsolidatedJointBusiness_9C59F67BF3D978409ABC1626706F9FF6" xlink:type="locator" />
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    <link:label id="lab_us-gaap_OtherSalesRevenueNet_679FEB7318ABFAD7E758162670708228_terseLabel_en-US" xlink:label="lab_us-gaap_OtherSalesRevenueNet_679FEB7318ABFAD7E758162670708228" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other revenues from external customers</link:label>
    <link:label id="lab_us-gaap_OtherSalesRevenueNet_679FEB7318ABFAD7E758162670708228_label_en-US" xlink:label="lab_us-gaap_OtherSalesRevenueNet_679FEB7318ABFAD7E758162670708228" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Revenue, Net</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherSalesRevenueNet" xlink:label="loc_us-gaap_OtherSalesRevenueNet_679FEB7318ABFAD7E758162670708228" xlink:type="locator" />
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    <link:label id="lab_us-gaap_NoncurrentAssets_3F047D578505B480DBDB1626707054F1_verboseLabel_en-US" xlink:label="lab_us-gaap_NoncurrentAssets_3F047D578505B480DBDB1626707054F1" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Long-lived assets</link:label>
    <link:label id="lab_us-gaap_NoncurrentAssets_3F047D578505B480DBDB1626707054F1_label_en-US" xlink:label="lab_us-gaap_NoncurrentAssets_3F047D578505B480DBDB1626707054F1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-Lived Assets</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NoncurrentAssets" xlink:label="loc_us-gaap_NoncurrentAssets_3F047D578505B480DBDB1626707054F1" xlink:type="locator" />
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    <link:label id="lab_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_0845C7570028B143D202B0034AB2B2F8_label_en-US" xlink:label="lab_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_0845C7570028B143D202B0034AB2B2F8" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Business Acquisitions, by Acquisition [Table]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_0845C7570028B143D202B0034AB2B2F8" xlink:type="locator" />
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    <link:label id="lab_biib_StxOneHundredMember_2010E03662AF7FE9C6D8B0034AB39852_terseLabel_en-US" xlink:label="lab_biib_StxOneHundredMember_2010E03662AF7FE9C6D8B0034AB39852" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">STX One Hundred</link:label>
    <link:label id="lab_biib_StxOneHundredMember_2010E03662AF7FE9C6D8B0034AB39852_label_en-US" xlink:label="lab_biib_StxOneHundredMember_2010E03662AF7FE9C6D8B0034AB39852" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">STX One Hundred [Member]</link:label>
    <link:label id="lab_biib_StxOneHundredMember_2010E03662AF7FE9C6D8B0034AB39852_documentation_en-US" xlink:label="lab_biib_StxOneHundredMember_2010E03662AF7FE9C6D8B0034AB39852" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">STX one hundred.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_StxOneHundredMember" xlink:label="loc_biib_StxOneHundredMember_2010E03662AF7FE9C6D8B0034AB39852" xlink:type="locator" />
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    <link:label id="lab_us-gaap_BusinessAcquisitionAxis_58807C38994EA4204D43B0034AB340C1_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionAxis_58807C38994EA4204D43B0034AB340C1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Business Acquisition [Axis]</link:label>
    <link:label id="lab_us-gaap_BusinessAcquisitionAxis_58807C38994EA4204D43B0034AB340C1_label_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionAxis_58807C38994EA4204D43B0034AB340C1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Acquisition [Axis]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_58807C38994EA4204D43B0034AB340C1" xlink:type="locator" />
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    <link:label id="lab_us-gaap_BusinessAcquisitionAcquireeDomain_EE5A4372AE16036112E9B0034AB3DE5D_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionAcquireeDomain_EE5A4372AE16036112E9B0034AB3DE5D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Business Acquisition, Acquiree [Domain]</link:label>
    <link:label id="lab_us-gaap_BusinessAcquisitionAcquireeDomain_EE5A4372AE16036112E9B0034AB3DE5D_label_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionAcquireeDomain_EE5A4372AE16036112E9B0034AB3DE5D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Acquisition, Acquiree [Domain]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_EE5A4372AE16036112E9B0034AB3DE5D" xlink:type="locator" />
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    <link:label id="lab_biib_StromedixMember_95AC00F8D70733D57DC3B0034AB359E7_verboseLabel_en-US" xlink:label="lab_biib_StromedixMember_95AC00F8D70733D57DC3B0034AB359E7" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Stromedix, Inc.</link:label>
    <link:label id="lab_biib_StromedixMember_95AC00F8D70733D57DC3B0034AB359E7_label_en-US" xlink:label="lab_biib_StromedixMember_95AC00F8D70733D57DC3B0034AB359E7" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Stromedix [Member]</link:label>
    <link:label id="lab_biib_StromedixMember_95AC00F8D70733D57DC3B0034AB359E7_documentation_en-US" xlink:label="lab_biib_StromedixMember_95AC00F8D70733D57DC3B0034AB359E7" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Stromedix.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_StromedixMember" xlink:label="loc_biib_StromedixMember_95AC00F8D70733D57DC3B0034AB359E7" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_biib_StromedixMember_95AC00F8D70733D57DC3B0034AB359E7" xlink:to="lab_biib_StromedixMember_95AC00F8D70733D57DC3B0034AB359E7" xlink:type="arc" />
    <link:label id="lab_biib_CorporateJointVentureInvestmentsMember_B577EE1AB099252DE75FB0034AB31EDD_terseLabel_en-US" xlink:label="lab_biib_CorporateJointVentureInvestmentsMember_B577EE1AB099252DE75FB0034AB31EDD" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Biogen Dompe SRL and Biogen Dompe Switzerland GmbH</link:label>
    <link:label id="lab_biib_CorporateJointVentureInvestmentsMember_B577EE1AB099252DE75FB0034AB31EDD_label_en-US" xlink:label="lab_biib_CorporateJointVentureInvestmentsMember_B577EE1AB099252DE75FB0034AB31EDD" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Corporate Joint Venture Investments Member</link:label>
    <link:label id="lab_biib_CorporateJointVentureInvestmentsMember_B577EE1AB099252DE75FB0034AB31EDD_documentation_en-US" xlink:label="lab_biib_CorporateJointVentureInvestmentsMember_B577EE1AB099252DE75FB0034AB31EDD" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Corporate Joint Venture Investments.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_CorporateJointVentureInvestmentsMember" xlink:label="loc_biib_CorporateJointVentureInvestmentsMember_B577EE1AB099252DE75FB0034AB31EDD" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_biib_CorporateJointVentureInvestmentsMember_B577EE1AB099252DE75FB0034AB31EDD" xlink:to="lab_biib_CorporateJointVentureInvestmentsMember_B577EE1AB099252DE75FB0034AB31EDD" xlink:type="arc" />
    <link:label id="lab_biib_BiogenDompeSrlMember_B29B3BFACF0D0E1472CAB0034AB351A4_terseLabel_en-US" xlink:label="lab_biib_BiogenDompeSrlMember_B29B3BFACF0D0E1472CAB0034AB351A4" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Biogen Dompe SRL</link:label>
    <link:label id="lab_biib_BiogenDompeSrlMember_B29B3BFACF0D0E1472CAB0034AB351A4_label_en-US" xlink:label="lab_biib_BiogenDompeSrlMember_B29B3BFACF0D0E1472CAB0034AB351A4" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Biogen Dompe SRL [Member]</link:label>
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    <link:label id="lab_biib_BiogenIdecInternationalNeuroscienceMember_126F48D6B2A752A18240B0034AB326FB_documentation_en-US" xlink:label="lab_biib_BiogenIdecInternationalNeuroscienceMember_126F48D6B2A752A18240B0034AB326FB" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Biogen idec international neuroscience.</link:label>
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    <link:label id="lab_biib_BiogenIdecHemophiliaMember_589698186D93ABD17CA5B0034AB3A220_terseLabel_en-US" xlink:label="lab_biib_BiogenIdecHemophiliaMember_589698186D93ABD17CA5B0034AB3A220" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Biogen Idec Hemophilia</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_BusinessAcquisitionCostOfAcquiredEntityCashPaid" xlink:label="loc_us-gaap_BusinessAcquisitionCostOfAcquiredEntityCashPaid_205563DE083F73F910BDB0034AB39AB2" xlink:type="locator" />
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    <link:label id="lab_us-gaap_BusinessAcquisitionContingentConsiderationPotentialCashPayment_EC1B74D7A415392040BBB0034AB3E7AD_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionContingentConsiderationPotentialCashPayment_EC1B74D7A415392040BBB0034AB3E7AD" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Value of contingent consideration</link:label>
    <link:label id="lab_us-gaap_BusinessAcquisitionContingentConsiderationPotentialCashPayment_EC1B74D7A415392040BBB0034AB3E7AD_label_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionContingentConsiderationPotentialCashPayment_EC1B74D7A415392040BBB0034AB3E7AD" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Acquisition, Contingent Consideration, Potential Cash Payment</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_BusinessAcquisitionContingentConsiderationPotentialCashPayment" xlink:label="loc_us-gaap_BusinessAcquisitionContingentConsiderationPotentialCashPayment_EC1B74D7A415392040BBB0034AB3E7AD" xlink:type="locator" />
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    <link:label id="lab_us-gaap_BusinessAcquisitionContingentConsiderationAtFairValue_B871EF8E0B536E15102FB0034AB3768D_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionContingentConsiderationAtFairValue_B871EF8E0B536E15102FB0034AB3768D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fair value of contingent consideration</link:label>
    <link:label id="lab_us-gaap_BusinessAcquisitionContingentConsiderationAtFairValue_B871EF8E0B536E15102FB0034AB3768D_label_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionContingentConsiderationAtFairValue_B871EF8E0B536E15102FB0034AB3768D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Acquisition, Contingent Consideration, at Fair Value</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_BusinessAcquisitionContingentConsiderationAtFairValue" xlink:label="loc_us-gaap_BusinessAcquisitionContingentConsiderationAtFairValue_B871EF8E0B536E15102FB0034AB3768D" xlink:type="locator" />
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    <link:label id="lab_biib_FairValueInProcessResearchAndDevelopmentDiscountRate_5791F82DA979695827FAB0034AB35A14_terseLabel_en-US" xlink:label="lab_biib_FairValueInProcessResearchAndDevelopmentDiscountRate_5791F82DA979695827FAB0034AB35A14" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Discount rate used to calculate fair value of in process research and development</link:label>
    <link:label id="lab_biib_FairValueInProcessResearchAndDevelopmentDiscountRate_5791F82DA979695827FAB0034AB35A14_label_en-US" xlink:label="lab_biib_FairValueInProcessResearchAndDevelopmentDiscountRate_5791F82DA979695827FAB0034AB35A14" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value In Process Research And Development Discount Rate</link:label>
    <link:label id="lab_biib_FairValueInProcessResearchAndDevelopmentDiscountRate_5791F82DA979695827FAB0034AB35A14_documentation_en-US" xlink:label="lab_biib_FairValueInProcessResearchAndDevelopmentDiscountRate_5791F82DA979695827FAB0034AB35A14" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Discount rate used to calculate fair value of in process research and development.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_FairValueInProcessResearchAndDevelopmentDiscountRate" xlink:label="loc_biib_FairValueInProcessResearchAndDevelopmentDiscountRate_5791F82DA979695827FAB0034AB35A14" xlink:type="locator" />
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    <link:label id="lab_us-gaap_BusinessAcquisitionPurchasePriceAllocationAmortizableIntangibleAssets_2AAF7C875870A51B53ABB0034AB398E7_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionPurchasePriceAllocationAmortizableIntangibleAssets_2AAF7C875870A51B53ABB0034AB398E7" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">In-process research and development</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_BusinessAcquisitionPurchasePriceAllocationAmortizableIntangibleAssets" xlink:label="loc_us-gaap_BusinessAcquisitionPurchasePriceAllocationAmortizableIntangibleAssets_2AAF7C875870A51B53ABB0034AB398E7" xlink:type="locator" />
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    <link:label id="lab_biib_RemainingCostToCompletePrimaryIndication_C66707A0357CAB2CACDCB0034AB35D17_terseLabel_en-US" xlink:label="lab_biib_RemainingCostToCompletePrimaryIndication_C66707A0357CAB2CACDCB0034AB35D17" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Remaining cost to complete primary indication</link:label>
    <link:label id="lab_biib_RemainingCostToCompletePrimaryIndication_C66707A0357CAB2CACDCB0034AB35D17_label_en-US" xlink:label="lab_biib_RemainingCostToCompletePrimaryIndication_C66707A0357CAB2CACDCB0034AB35D17" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Remaining Cost To Complete Primary Indication</link:label>
    <link:label id="lab_biib_RemainingCostToCompletePrimaryIndication_C66707A0357CAB2CACDCB0034AB35D17_documentation_en-US" xlink:label="lab_biib_RemainingCostToCompletePrimaryIndication_C66707A0357CAB2CACDCB0034AB35D17" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Remaining cost to complete primary indication.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_RemainingCostToCompletePrimaryIndication" xlink:label="loc_biib_RemainingCostToCompletePrimaryIndication_C66707A0357CAB2CACDCB0034AB35D17" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_biib_RemainingCostToCompletePrimaryIndication_C66707A0357CAB2CACDCB0034AB35D17" xlink:to="lab_biib_RemainingCostToCompletePrimaryIndication_C66707A0357CAB2CACDCB0034AB35D17" xlink:type="arc" />
    <link:label id="lab_us-gaap_EquityMethodInvestmentOwnershipPercentage_6660D15C0F8D6E6C4640B0034AB4CC3B_terseLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentOwnershipPercentage_6660D15C0F8D6E6C4640B0034AB4CC3B" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Percentage of equity interest to the portion of total capital stock</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestmentOwnershipPercentage_6660D15C0F8D6E6C4640B0034AB4CC3B_label_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentOwnershipPercentage_6660D15C0F8D6E6C4640B0034AB4CC3B" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investment, Ownership Percentage</link:label>
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    <link:label id="lab_biib_GainLossRecognizedDuringAcquisitionRelatingToPreExistingEquityInterest_2A82EE1670C6062DE068B0034AB4246F_terseLabel_en-US" xlink:label="lab_biib_GainLossRecognizedDuringAcquisitionRelatingToPreExistingEquityInterest_2A82EE1670C6062DE068B0034AB4246F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Recognized gain</link:label>
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    <link:label id="lab_biib_GainLossRecognizedDuringAcquisitionRelatingToPreExistingEquityInterest_2A82EE1670C6062DE068B0034AB4246F_documentation_en-US" xlink:label="lab_biib_GainLossRecognizedDuringAcquisitionRelatingToPreExistingEquityInterest_2A82EE1670C6062DE068B0034AB4246F" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Gain/loss recognized during acquisition relating to pre-existing equity interest.</link:label>
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    <link:label id="lab_us-gaap_BusinessCombinationAcquiredReceivablesFairValue_A09EA3EB427E5854CB67B0034AB46354_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessCombinationAcquiredReceivablesFairValue_A09EA3EB427E5854CB67B0034AB46354" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Receivables purchased as part of acquisition</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_BusinessCombinationAcquiredReceivablesFairValue" xlink:label="loc_us-gaap_BusinessCombinationAcquiredReceivablesFairValue_A09EA3EB427E5854CB67B0034AB46354" xlink:type="locator" />
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    <link:label id="lab_us-gaap_GainLossOnDispositionOfAssets_31160A62C34FE6560CFCB0034AB4C541_terseLabel_en-US" xlink:label="lab_us-gaap_GainLossOnDispositionOfAssets_31160A62C34FE6560CFCB0034AB4C541" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Loss recognized upon disposition</link:label>
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    <link:label id="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_9AB5C7FE4F5A7D0247B15E00F79B2DE3_label_en-US" xlink:label="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_9AB5C7FE4F5A7D0247B15E00F79B2DE3" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Organization, Consolidation and Presentation of Financial Statements [Abstract]</link:label>
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    <link:label id="lab_us-gaap_SupplementalCashFlowInformationAbstract_EC1A42F776A647ADC2BE5E00F79BD544_terseLabel_en-US" xlink:label="lab_us-gaap_SupplementalCashFlowInformationAbstract_EC1A42F776A647ADC2BE5E00F79BD544" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash Paid During the Year</link:label>
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    <link:label id="lab_us-gaap_InterestPaidNet_1D71B6985AA5DCEC21855E00F79B7451_terseLabel_en-US" xlink:label="lab_us-gaap_InterestPaidNet_1D71B6985AA5DCEC21855E00F79B7451" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest</link:label>
    <link:label id="lab_us-gaap_InterestPaidNet_1D71B6985AA5DCEC21855E00F79B7451_label_en-US" xlink:label="lab_us-gaap_InterestPaidNet_1D71B6985AA5DCEC21855E00F79B7451" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Paid, Net</link:label>
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    <link:label id="lab_us-gaap_IncomeTaxesPaidNet_4A2B1AEF6267CDC1DB385E00F79B69FE_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxesPaidNet_4A2B1AEF6267CDC1DB385E00F79B69FE" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Income taxes</link:label>
    <link:label id="lab_us-gaap_IncomeTaxesPaidNet_4A2B1AEF6267CDC1DB385E00F79B69FE_label_en-US" xlink:label="lab_us-gaap_IncomeTaxesPaidNet_4A2B1AEF6267CDC1DB385E00F79B69FE" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Taxes Paid, Net</link:label>
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    <link:label id="lab_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax_715D1B4FB442C0DD515C5E00F79C437E_verboseLabel_en-US" xlink:label="lab_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax_715D1B4FB442C0DD515C5E00F79C437E" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Foreign exchange gains (losses), net</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" xlink:label="loc_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax_715D1B4FB442C0DD515C5E00F79C437E" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax_715D1B4FB442C0DD515C5E00F79C437E" xlink:to="lab_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax_715D1B4FB442C0DD515C5E00F79C437E" xlink:type="arc" />
    <link:label id="lab_biib_OtherIncomeExpenseNet_04AC0D0D72E3D62DD94F5E00F79C113C_verboseLabel_en-US" xlink:label="lab_biib_OtherIncomeExpenseNet_04AC0D0D72E3D62DD94F5E00F79C113C" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Other, net</link:label>
    <link:label id="lab_biib_OtherIncomeExpenseNet_04AC0D0D72E3D62DD94F5E00F79C113C_label_en-US" xlink:label="lab_biib_OtherIncomeExpenseNet_04AC0D0D72E3D62DD94F5E00F79C113C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Income Expense Net</link:label>
    <link:label id="lab_biib_OtherIncomeExpenseNet_04AC0D0D72E3D62DD94F5E00F79C113C_documentation_en-US" xlink:label="lab_biib_OtherIncomeExpenseNet_04AC0D0D72E3D62DD94F5E00F79C113C" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The amount of other nonoperating income and expense, which does not qualify for separate disclosure on the income statement.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_OtherIncomeExpenseNet" xlink:label="loc_biib_OtherIncomeExpenseNet_04AC0D0D72E3D62DD94F5E00F79C113C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_biib_OtherIncomeExpenseNet_04AC0D0D72E3D62DD94F5E00F79C113C" xlink:to="lab_biib_OtherIncomeExpenseNet_04AC0D0D72E3D62DD94F5E00F79C113C" xlink:type="arc" />
    <link:label id="lab_us-gaap_OtherNonoperatingIncomeExpense_9A02158DEC12A6A5C6075E00F79C1E64_totalLabel_en-US" xlink:label="lab_us-gaap_OtherNonoperatingIncomeExpense_9A02158DEC12A6A5C6075E00F79C1E64" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total other income (expense), net</link:label>
    <link:label id="lab_us-gaap_OtherNonoperatingIncomeExpense_9A02158DEC12A6A5C6075E00F79C1E64_label_en-US" xlink:label="lab_us-gaap_OtherNonoperatingIncomeExpense_9A02158DEC12A6A5C6075E00F79C1E64" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Nonoperating Income (Expense)</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_9A02158DEC12A6A5C6075E00F79C1E64" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherNonoperatingIncomeExpense_9A02158DEC12A6A5C6075E00F79C1E64" xlink:to="lab_us-gaap_OtherNonoperatingIncomeExpense_9A02158DEC12A6A5C6075E00F79C1E64" xlink:type="arc" />
    <link:label id="lab_us-gaap_AccruedLiabilitiesCurrentAbstract_3927FEC12DF607566DB65E00F79CC99F_verboseLabel_en-US" xlink:label="lab_us-gaap_AccruedLiabilitiesCurrentAbstract_3927FEC12DF607566DB65E00F79CC99F" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Accrued Expenses and Other</link:label>
    <link:label id="lab_us-gaap_AccruedLiabilitiesCurrentAbstract_3927FEC12DF607566DB65E00F79CC99F_label_en-US" xlink:label="lab_us-gaap_AccruedLiabilitiesCurrentAbstract_3927FEC12DF607566DB65E00F79CC99F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accrued Liabilities, Current [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccruedLiabilitiesCurrentAbstract" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrentAbstract_3927FEC12DF607566DB65E00F79CC99F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccruedLiabilitiesCurrentAbstract_3927FEC12DF607566DB65E00F79CC99F" xlink:to="lab_us-gaap_AccruedLiabilitiesCurrentAbstract_3927FEC12DF607566DB65E00F79CC99F" xlink:type="arc" />
    <link:label id="lab_us-gaap_EmployeeRelatedLiabilitiesCurrent_512B2595AEB2C0A5CC6D5E00F79CF7AE_verboseLabel_en-US" xlink:label="lab_us-gaap_EmployeeRelatedLiabilitiesCurrent_512B2595AEB2C0A5CC6D5E00F79CF7AE" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Employee compensation and benefits</link:label>
    <link:label id="lab_us-gaap_EmployeeRelatedLiabilitiesCurrent_512B2595AEB2C0A5CC6D5E00F79CF7AE_label_en-US" xlink:label="lab_us-gaap_EmployeeRelatedLiabilitiesCurrent_512B2595AEB2C0A5CC6D5E00F79CF7AE" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Employee-related Liabilities, Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:label="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_512B2595AEB2C0A5CC6D5E00F79CF7AE" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_512B2595AEB2C0A5CC6D5E00F79CF7AE" xlink:to="lab_us-gaap_EmployeeRelatedLiabilitiesCurrent_512B2595AEB2C0A5CC6D5E00F79CF7AE" xlink:type="arc" />
    <link:label id="lab_biib_RevenueRelatedRebates_9102AB20B7031CF990EF5E00F79CF19F_verboseLabel_en-US" xlink:label="lab_biib_RevenueRelatedRebates_9102AB20B7031CF990EF5E00F79CF19F" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Revenue-related rebates</link:label>
    <link:label id="lab_biib_RevenueRelatedRebates_9102AB20B7031CF990EF5E00F79CF19F_label_en-US" xlink:label="lab_biib_RevenueRelatedRebates_9102AB20B7031CF990EF5E00F79CF19F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenue Related Rebates</link:label>
    <link:label id="lab_biib_RevenueRelatedRebates_9102AB20B7031CF990EF5E00F79CF19F_documentation_en-US" xlink:label="lab_biib_RevenueRelatedRebates_9102AB20B7031CF990EF5E00F79CF19F" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">This element represents the accrued rebates at the balance sheet date.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_RevenueRelatedRebates" xlink:label="loc_biib_RevenueRelatedRebates_9102AB20B7031CF990EF5E00F79CF19F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_biib_RevenueRelatedRebates_9102AB20B7031CF990EF5E00F79CF19F" xlink:to="lab_biib_RevenueRelatedRebates_9102AB20B7031CF990EF5E00F79CF19F" xlink:type="arc" />
    <link:label id="lab_us-gaap_DeferredRevenueCurrent_E635E80B1A6D7317B2015E00F79CC3D7_verboseLabel_en-US" xlink:label="lab_us-gaap_DeferredRevenueCurrent_E635E80B1A6D7317B2015E00F79CC3D7" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Deferred revenue</link:label>
    <link:label id="lab_us-gaap_DeferredRevenueCurrent_E635E80B1A6D7317B2015E00F79CC3D7_label_en-US" xlink:label="lab_us-gaap_DeferredRevenueCurrent_E635E80B1A6D7317B2015E00F79CC3D7" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Revenue, Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DeferredRevenueCurrent" xlink:label="loc_us-gaap_DeferredRevenueCurrent_E635E80B1A6D7317B2015E00F79CC3D7" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredRevenueCurrent_E635E80B1A6D7317B2015E00F79CC3D7" xlink:to="lab_us-gaap_DeferredRevenueCurrent_E635E80B1A6D7317B2015E00F79CC3D7" xlink:type="arc" />
    <link:label id="lab_biib_ClinicalDevelopmentExpenses_53E85D0987DB3F8AE9675E00F79C21B4_verboseLabel_en-US" xlink:label="lab_biib_ClinicalDevelopmentExpenses_53E85D0987DB3F8AE9675E00F79C21B4" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Clinical development expenses</link:label>
    <link:label id="lab_biib_ClinicalDevelopmentExpenses_53E85D0987DB3F8AE9675E00F79C21B4_label_en-US" xlink:label="lab_biib_ClinicalDevelopmentExpenses_53E85D0987DB3F8AE9675E00F79C21B4" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Clinical Development Expenses</link:label>
    <link:label id="lab_biib_ClinicalDevelopmentExpenses_53E85D0987DB3F8AE9675E00F79C21B4_documentation_en-US" xlink:label="lab_biib_ClinicalDevelopmentExpenses_53E85D0987DB3F8AE9675E00F79C21B4" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Carrying amount as of the balance sheet date for expenses incurred related to clinical development activities due within one year.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_ClinicalDevelopmentExpenses" xlink:label="loc_biib_ClinicalDevelopmentExpenses_53E85D0987DB3F8AE9675E00F79C21B4" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_biib_ClinicalDevelopmentExpenses_53E85D0987DB3F8AE9675E00F79C21B4" xlink:to="lab_biib_ClinicalDevelopmentExpenses_53E85D0987DB3F8AE9675E00F79C21B4" xlink:type="arc" />
    <link:label id="lab_us-gaap_AccruedRoyaltiesCurrent_EEDE5EF8C02245CF185B5E00F79CDD53_verboseLabel_en-US" xlink:label="lab_us-gaap_AccruedRoyaltiesCurrent_EEDE5EF8C02245CF185B5E00F79CDD53" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Royalties and licensing fees</link:label>
    <link:label id="lab_us-gaap_AccruedRoyaltiesCurrent_EEDE5EF8C02245CF185B5E00F79CDD53_label_en-US" xlink:label="lab_us-gaap_AccruedRoyaltiesCurrent_EEDE5EF8C02245CF185B5E00F79CDD53" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accrued Royalties, Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccruedRoyaltiesCurrent" xlink:label="loc_us-gaap_AccruedRoyaltiesCurrent_EEDE5EF8C02245CF185B5E00F79CDD53" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccruedRoyaltiesCurrent_EEDE5EF8C02245CF185B5E00F79CDD53" xlink:to="lab_us-gaap_AccruedRoyaltiesCurrent_EEDE5EF8C02245CF185B5E00F79CDD53" xlink:type="arc" />
    <link:label id="lab_biib_CollaborationExpenses_301AA0805B09E113DAEF5E00F79C0E54_verboseLabel_en-US" xlink:label="lab_biib_CollaborationExpenses_301AA0805B09E113DAEF5E00F79C0E54" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Collaboration expenses</link:label>
    <link:label id="lab_biib_CollaborationExpenses_301AA0805B09E113DAEF5E00F79C0E54_label_en-US" xlink:label="lab_biib_CollaborationExpenses_301AA0805B09E113DAEF5E00F79C0E54" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Collaboration Expenses</link:label>
    <link:label id="lab_biib_CollaborationExpenses_301AA0805B09E113DAEF5E00F79C0E54_documentation_en-US" xlink:label="lab_biib_CollaborationExpenses_301AA0805B09E113DAEF5E00F79C0E54" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Carrying amount as of the balance sheet date of payments due to collaborations excluding unconsolidated joint business.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_CollaborationExpenses" xlink:label="loc_biib_CollaborationExpenses_301AA0805B09E113DAEF5E00F79C0E54" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_biib_CollaborationExpenses_301AA0805B09E113DAEF5E00F79C0E54" xlink:to="lab_biib_CollaborationExpenses_301AA0805B09E113DAEF5E00F79C0E54" xlink:type="arc" />
    <link:label id="lab_biib_CurrentPortionOfContingentConsiderationObligations_327F84A5C7B434FC81135E00F79C38BB_verboseLabel_en-US" xlink:label="lab_biib_CurrentPortionOfContingentConsiderationObligations_327F84A5C7B434FC81135E00F79C38BB" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Current portion of contingent consideration obligations</link:label>
    <link:label id="lab_biib_CurrentPortionOfContingentConsiderationObligations_327F84A5C7B434FC81135E00F79C38BB_label_en-US" xlink:label="lab_biib_CurrentPortionOfContingentConsiderationObligations_327F84A5C7B434FC81135E00F79C38BB" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Current Portion Of Contingent Consideration Obligations</link:label>
    <link:label id="lab_biib_CurrentPortionOfContingentConsiderationObligations_327F84A5C7B434FC81135E00F79C38BB_documentation_en-US" xlink:label="lab_biib_CurrentPortionOfContingentConsiderationObligations_327F84A5C7B434FC81135E00F79C38BB" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Current portion of contingent consideration obligations.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_CurrentPortionOfContingentConsiderationObligations" xlink:label="loc_biib_CurrentPortionOfContingentConsiderationObligations_327F84A5C7B434FC81135E00F79C38BB" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_biib_CurrentPortionOfContingentConsiderationObligations_327F84A5C7B434FC81135E00F79C38BB" xlink:to="lab_biib_CurrentPortionOfContingentConsiderationObligations_327F84A5C7B434FC81135E00F79C38BB" xlink:type="arc" />
    <link:label id="lab_biib_OtherAccruedExpensesAndOther_F6717FDF4F89E10233765E00F79CC847_verboseLabel_en-US" xlink:label="lab_biib_OtherAccruedExpensesAndOther_F6717FDF4F89E10233765E00F79CC847" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Other</link:label>
    <link:label id="lab_biib_OtherAccruedExpensesAndOther_F6717FDF4F89E10233765E00F79CC847_label_en-US" xlink:label="lab_biib_OtherAccruedExpensesAndOther_F6717FDF4F89E10233765E00F79CC847" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Accrued Expenses And Other</link:label>
    <link:label id="lab_biib_OtherAccruedExpensesAndOther_F6717FDF4F89E10233765E00F79CC847_documentation_en-US" xlink:label="lab_biib_OtherAccruedExpensesAndOther_F6717FDF4F89E10233765E00F79CC847" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Carrying amount as of the balance sheet date of other accrued expenses and other, excluding amounts separately identified within this table.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_OtherAccruedExpensesAndOther" xlink:label="loc_biib_OtherAccruedExpensesAndOther_F6717FDF4F89E10233765E00F79CC847" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_biib_OtherAccruedExpensesAndOther_F6717FDF4F89E10233765E00F79CC847" xlink:to="lab_biib_OtherAccruedExpensesAndOther_F6717FDF4F89E10233765E00F79CC847" xlink:type="arc" />
    <link:label id="lab_us-gaap_OtherLiabilitiesCurrent_19D69E60DCE30B8CF0645E00F79C433C_totalLabel_en-US" xlink:label="lab_us-gaap_OtherLiabilitiesCurrent_19D69E60DCE30B8CF0645E00F79C433C" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total accrued expenses and other</link:label>
    <link:label id="lab_us-gaap_OtherLiabilitiesCurrent_19D69E60DCE30B8CF0645E00F79C433C_label_en-US" xlink:label="lab_us-gaap_OtherLiabilitiesCurrent_19D69E60DCE30B8CF0645E00F79C433C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Liabilities, Current</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherLiabilitiesCurrent" xlink:label="loc_us-gaap_OtherLiabilitiesCurrent_19D69E60DCE30B8CF0645E00F79C433C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherLiabilitiesCurrent_19D69E60DCE30B8CF0645E00F79C433C" xlink:to="lab_us-gaap_OtherLiabilitiesCurrent_19D69E60DCE30B8CF0645E00F79C433C" xlink:type="arc" />
    <link:label id="lab_biib_FacilityLocationAxis_059B254B4EE327BDE75E9AA05D10E212_terseLabel_en-US" xlink:label="lab_biib_FacilityLocationAxis_059B254B4EE327BDE75E9AA05D10E212" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Facility Location [Axis]</link:label>
    <link:label id="lab_biib_FacilityLocationAxis_059B254B4EE327BDE75E9AA05D10E212_label_en-US" xlink:label="lab_biib_FacilityLocationAxis_059B254B4EE327BDE75E9AA05D10E212" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Facility Location [Axis]</link:label>
    <link:label id="lab_biib_FacilityLocationAxis_059B254B4EE327BDE75E9AA05D10E212_documentation_en-US" xlink:label="lab_biib_FacilityLocationAxis_059B254B4EE327BDE75E9AA05D10E212" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">-- None. No documentation exists for this element. --</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_FacilityLocationAxis" xlink:label="loc_biib_FacilityLocationAxis_059B254B4EE327BDE75E9AA05D10E212" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_biib_FacilityLocationAxis_059B254B4EE327BDE75E9AA05D10E212" xlink:to="lab_biib_FacilityLocationAxis_059B254B4EE327BDE75E9AA05D10E212" xlink:type="arc" />
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    <link:label id="lab_biib_FacilityLocationDomain_4E101FDF4E4307FAD8479AA05D10EBB9_label_en-US" xlink:label="lab_biib_FacilityLocationDomain_4E101FDF4E4307FAD8479AA05D10EBB9" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Facility Location [Domain]</link:label>
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    <link:label id="lab_biib_SeniorNotesSixPointEightSevenFivePercentDueTwentyEighteenMember_41624B682D0A3C3A687B3A85EAB8F0D3_verboseLabel_en-US" xlink:label="lab_biib_SeniorNotesSixPointEightSevenFivePercentDueTwentyEighteenMember_41624B682D0A3C3A687B3A85EAB8F0D3" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">6.875% Senior Notes due 2018</link:label>
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    <link:label id="lab_biib_VestingAxis_AC294DF4CE671000DC00911317C2DD14_documentation_en-US" xlink:label="lab_biib_VestingAxis_AC294DF4CE671000DC00911317C2DD14" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Vesting [Axis]</link:label>
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    <link:label id="lab_biib_VestingDomain_F00003E62056062445E8911317C27F6F_label_en-US" xlink:label="lab_biib_VestingDomain_F00003E62056062445E8911317C27F6F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Vesting [Domain]</link:label>
    <link:label id="lab_biib_VestingDomain_F00003E62056062445E8911317C27F6F_documentation_en-US" xlink:label="lab_biib_VestingDomain_F00003E62056062445E8911317C27F6F" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">[Domain] for Vesting [Axis]</link:label>
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    <link:label id="lab_biib_EmployeeMember_B9CE91518C6C561A7B7A911317C2A57F_terseLabel_en-US" xlink:label="lab_biib_EmployeeMember_B9CE91518C6C561A7B7A911317C2A57F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Employee</link:label>
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    <link:loc xlink:href="biib-20121231.xsd#biib_EmployeeMember" xlink:label="loc_biib_EmployeeMember_B9CE91518C6C561A7B7A911317C2A57F" xlink:type="locator" />
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    <link:loc xlink:href="biib-20121231.xsd#biib_ShareBasedCompensationPlanAxis" xlink:label="loc_biib_ShareBasedCompensationPlanAxis_2185D3DD317B6F1C1058911317C2DE8B" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_biib_ShareBasedCompensationPlanAxis_2185D3DD317B6F1C1058911317C2DE8B" xlink:to="lab_biib_ShareBasedCompensationPlanAxis_2185D3DD317B6F1C1058911317C2DE8B" xlink:type="arc" />
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    <link:loc xlink:href="biib-20121231.xsd#biib_ShareBasedCompensationPlanDomain" xlink:label="loc_biib_ShareBasedCompensationPlanDomain_F56DF54007E6EE9D21EA911317C289AC" xlink:type="locator" />
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    <link:loc xlink:href="biib-20121231.xsd#biib_DirectorsPlanMember" xlink:label="loc_biib_DirectorsPlanMember_A218528D13B73F939C54911317C2B8B9" xlink:type="locator" />
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    <link:label id="lab_biib_OmnibusPlansMember_882587ED06BEEF4FD629911317C2F839_terseLabel_en-US" xlink:label="lab_biib_OmnibusPlansMember_882587ED06BEEF4FD629911317C2F839" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Omnibus Plans</link:label>
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    <link:label id="lab_us-gaap_EmployeeServiceShareBasedCompensationCashFlowEffectCashUsedToSettleAwards_F994A148309E1431D976911317C48A0A_verboseLabel_en-US" xlink:label="lab_us-gaap_EmployeeServiceShareBasedCompensationCashFlowEffectCashUsedToSettleAwards_F994A148309E1431D976911317C48A0A" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Cash in settlement of CSPS awards upon vesting</link:label>
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    <link:label id="lab_us-gaap_ComprehensiveIncomeNoteTextBlock_277C75B30D1472D4F265962687C82DE7_terseLabel_en-US" xlink:label="lab_us-gaap_ComprehensiveIncomeNoteTextBlock_277C75B30D1472D4F265962687C82DE7" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Comprehensive Income (Loss) Note</link:label>
    <link:label id="lab_us-gaap_ComprehensiveIncomeNoteTextBlock_277C75B30D1472D4F265962687C82DE7_label_en-US" xlink:label="lab_us-gaap_ComprehensiveIncomeNoteTextBlock_277C75B30D1472D4F265962687C82DE7" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Comprehensive Income (Loss) Note [Text Block]</link:label>
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    <link:label id="lab_us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract_337B7AF2596085663727A8259FAD4AEC_label_en-US" xlink:label="lab_us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract_337B7AF2596085663727A8259FAD4AEC" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statement of Other Comprehensive Income [Abstract]</link:label>
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    <link:label id="lab_us-gaap_NetIncomeLoss_6B6F1C09D0662E0387E1A8259FB086BB_terseLabel_en-US" xlink:label="lab_us-gaap_NetIncomeLoss_6B6F1C09D0662E0387E1A8259FB086BB" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net income</link:label>
    <link:label id="lab_us-gaap_NetIncomeLoss_6B6F1C09D0662E0387E1A8259FB086BB_label_en-US" xlink:label="lab_us-gaap_NetIncomeLoss_6B6F1C09D0662E0387E1A8259FB086BB" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Income (Loss) Attributable to Parent</link:label>
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    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetIncomeLoss_6B6F1C09D0662E0387E1A8259FB086BB" xlink:to="lab_us-gaap_NetIncomeLoss_6B6F1C09D0662E0387E1A8259FB086BB" xlink:type="arc" />
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract_B1F4FC7639153C1E7A75A8259FB11580_verboseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract_B1F4FC7639153C1E7A75A8259FB11580" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Other comprehensive income:</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract_B1F4FC7639153C1E7A75A8259FB11580_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract_B1F4FC7639153C1E7A75A8259FB11580" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract_B1F4FC7639153C1E7A75A8259FB11580" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract_B1F4FC7639153C1E7A75A8259FB11580" xlink:to="lab_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract_B1F4FC7639153C1E7A75A8259FB11580" xlink:type="arc" />
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_9ECB6606A25F630F75A0A8259FB1E805_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_9ECB6606A25F630F75A0A8259FB1E805" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Unrealized gains (losses) recognized during the period, net of tax of $2,940, $133 and $6,345</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_9ECB6606A25F630F75A0A8259FB1E805_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_9ECB6606A25F630F75A0A8259FB1E805" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_9ECB6606A25F630F75A0A8259FB1E805" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_9ECB6606A25F630F75A0A8259FB1E805" xlink:to="lab_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_9ECB6606A25F630F75A0A8259FB1E805" xlink:type="arc" />
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentForSaleOfSecuritiesIncludedInNetIncomeNetOfTax_E659CE6BE8D37A586A5CA8259FB1DF05_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentForSaleOfSecuritiesIncludedInNetIncomeNetOfTax_E659CE6BE8D37A586A5CA8259FB1DF05" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Less: reclassification adjustment for gains (losses) included in net income, net of tax of $486, $7,155 and $5,656</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentForSaleOfSecuritiesIncludedInNetIncomeNetOfTax_E659CE6BE8D37A586A5CA8259FB1DF05_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentForSaleOfSecuritiesIncludedInNetIncomeNetOfTax_E659CE6BE8D37A586A5CA8259FB1DF05" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Net of Tax</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentForSaleOfSecuritiesIncludedInNetIncomeNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentForSaleOfSecuritiesIncludedInNetIncomeNetOfTax_E659CE6BE8D37A586A5CA8259FB1DF05" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentForSaleOfSecuritiesIncludedInNetIncomeNetOfTax_E659CE6BE8D37A586A5CA8259FB1DF05" xlink:to="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentForSaleOfSecuritiesIncludedInNetIncomeNetOfTax_E659CE6BE8D37A586A5CA8259FB1DF05" xlink:type="arc" />
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax_64F29D0CEDDBB8921769A8259FB19148_totalLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax_64F29D0CEDDBB8921769A8259FB19148" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Unrealized gains (losses) on securities available for sale, net of tax of $2,454, $7,288 and $689</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax_64F29D0CEDDBB8921769A8259FB19148_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax_64F29D0CEDDBB8921769A8259FB19148" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax_64F29D0CEDDBB8921769A8259FB19148" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax_64F29D0CEDDBB8921769A8259FB19148" xlink:to="lab_us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax_64F29D0CEDDBB8921769A8259FB19148" xlink:type="arc" />
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax_D3FB594D66C1CC955984A8259FB15649_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax_D3FB594D66C1CC955984A8259FB15649" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Unrealized gains (losses) recognized during the period, net of tax of $1,396, $3,647 and $1,268</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax_D3FB594D66C1CC955984A8259FB15649_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax_D3FB594D66C1CC955984A8259FB15649" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax_D3FB594D66C1CC955984A8259FB15649" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax_D3FB594D66C1CC955984A8259FB15649" xlink:to="lab_us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodNetOfTax_D3FB594D66C1CC955984A8259FB15649" xlink:type="arc" />
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentOnDerivativesIncludedInNetIncomeNetOfTax_E4449EF748850C8B5395A8259FB181CB_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentOnDerivativesIncludedInNetIncomeNetOfTax_E4449EF748850C8B5395A8259FB181CB" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Less: reclassification adjustment for gains (losses) included in net income, net of tax of $3,360, $1,268 and $304</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentOnDerivativesIncludedInNetIncomeNetOfTax_E4449EF748850C8B5395A8259FB181CB_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentOnDerivativesIncludedInNetIncomeNetOfTax_E4449EF748850C8B5395A8259FB181CB" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, Net of Tax</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentOnDerivativesIncludedInNetIncomeNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentOnDerivativesIncludedInNetIncomeNetOfTax_E4449EF748850C8B5395A8259FB181CB" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentOnDerivativesIncludedInNetIncomeNetOfTax_E4449EF748850C8B5395A8259FB181CB" xlink:to="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentOnDerivativesIncludedInNetIncomeNetOfTax_E4449EF748850C8B5395A8259FB181CB" xlink:type="arc" />
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax_3D59AFA1ECD4FBC65422A8259FB2AA41_totalLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax_3D59AFA1ECD4FBC65422A8259FB2AA41" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Unrealized gains (losses) on foreign currency forward contracts, net of tax of $4,756, $4,915 and $964</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax_3D59AFA1ECD4FBC65422A8259FB2AA41_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax_3D59AFA1ECD4FBC65422A8259FB2AA41" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax_3D59AFA1ECD4FBC65422A8259FB2AA41" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax_3D59AFA1ECD4FBC65422A8259FB2AA41" xlink:to="lab_us-gaap_OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax_3D59AFA1ECD4FBC65422A8259FB2AA41" xlink:type="arc" />
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_B47D08CF44B70C43DAA5A8259FB2A213_negatedLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_B47D08CF44B70C43DAA5A8259FB2A213" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Unrealized gains (losses) on pension benefit obligation, net of tax</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_B47D08CF44B70C43DAA5A8259FB2A213" xlink:type="locator" />
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    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_389E422659F06CBE94E0A8259FB29347_verboseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_389E422659F06CBE94E0A8259FB29347" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Currency translation adjustment</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_389E422659F06CBE94E0A8259FB29347_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_389E422659F06CBE94E0A8259FB29347" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_389E422659F06CBE94E0A8259FB29347" xlink:type="locator" />
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    <link:label id="lab_us-gaap_CollaborativeArrangementDisclosureTextBlock_1409D41B9EDA70A1F5E6962685D665BF_verboseLabel_en-US" xlink:label="lab_us-gaap_CollaborativeArrangementDisclosureTextBlock_1409D41B9EDA70A1F5E6962685D665BF" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Collaborative and Other Relationships</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CollaborativeArrangementDisclosureTextBlock" xlink:label="loc_us-gaap_CollaborativeArrangementDisclosureTextBlock_1409D41B9EDA70A1F5E6962685D665BF" xlink:type="locator" />
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    <link:label id="lab_biib_LitigationTextBlock_5A9F24F2300BDE7D6EAB8BD92EC796C3_verboseLabel_en-US" xlink:label="lab_biib_LitigationTextBlock_5A9F24F2300BDE7D6EAB8BD92EC796C3" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Litigation</link:label>
    <link:label id="lab_biib_LitigationTextBlock_5A9F24F2300BDE7D6EAB8BD92EC796C3_label_en-US" xlink:label="lab_biib_LitigationTextBlock_5A9F24F2300BDE7D6EAB8BD92EC796C3" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Litigation [Text Block]</link:label>
    <link:label id="lab_biib_LitigationTextBlock_5A9F24F2300BDE7D6EAB8BD92EC796C3_documentation_en-US" xlink:label="lab_biib_LitigationTextBlock_5A9F24F2300BDE7D6EAB8BD92EC796C3" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Litigation.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_LitigationTextBlock" xlink:label="loc_biib_LitigationTextBlock_5A9F24F2300BDE7D6EAB8BD92EC796C3" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_biib_LitigationTextBlock_5A9F24F2300BDE7D6EAB8BD92EC796C3" xlink:to="lab_biib_LitigationTextBlock_5A9F24F2300BDE7D6EAB8BD92EC796C3" xlink:type="arc" />
    <link:label id="lab_us-gaap_AccountingPoliciesAbstract_E2A89E859EF68BB9B9A8962688E9CD0E_label_en-US" xlink:label="lab_us-gaap_AccountingPoliciesAbstract_E2A89E859EF68BB9B9A8962688E9CD0E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounting Policies [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccountingPoliciesAbstract" xlink:label="loc_us-gaap_AccountingPoliciesAbstract_E2A89E859EF68BB9B9A8962688E9CD0E" xlink:type="locator" />
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    <link:label id="lab_biib_BusinessOverviewPolicyTextBlock_33EE41B1FED518AB379A962688E97932_terseLabel_en-US" xlink:label="lab_biib_BusinessOverviewPolicyTextBlock_33EE41B1FED518AB379A962688E97932" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Business Overview</link:label>
    <link:label id="lab_biib_BusinessOverviewPolicyTextBlock_33EE41B1FED518AB379A962688E97932_label_en-US" xlink:label="lab_biib_BusinessOverviewPolicyTextBlock_33EE41B1FED518AB379A962688E97932" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Overview [Policy Text Block]</link:label>
    <link:label id="lab_biib_BusinessOverviewPolicyTextBlock_33EE41B1FED518AB379A962688E97932_documentation_en-US" xlink:label="lab_biib_BusinessOverviewPolicyTextBlock_33EE41B1FED518AB379A962688E97932" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Describes an overview of the company and its operations.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_BusinessOverviewPolicyTextBlock" xlink:label="loc_biib_BusinessOverviewPolicyTextBlock_33EE41B1FED518AB379A962688E97932" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_biib_BusinessOverviewPolicyTextBlock_33EE41B1FED518AB379A962688E97932" xlink:to="lab_biib_BusinessOverviewPolicyTextBlock_33EE41B1FED518AB379A962688E97932" xlink:type="arc" />
    <link:label id="lab_us-gaap_ConsolidationPolicyTextBlock_FCC6702781840235FF36962688E98C5B_terseLabel_en-US" xlink:label="lab_us-gaap_ConsolidationPolicyTextBlock_FCC6702781840235FF36962688E98C5B" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Consolidation</link:label>
    <link:label id="lab_us-gaap_ConsolidationPolicyTextBlock_FCC6702781840235FF36962688E98C5B_label_en-US" xlink:label="lab_us-gaap_ConsolidationPolicyTextBlock_FCC6702781840235FF36962688E98C5B" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Consolidation, Policy [Policy Text Block]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ConsolidationPolicyTextBlock" xlink:label="loc_us-gaap_ConsolidationPolicyTextBlock_FCC6702781840235FF36962688E98C5B" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ConsolidationPolicyTextBlock_FCC6702781840235FF36962688E98C5B" xlink:to="lab_us-gaap_ConsolidationPolicyTextBlock_FCC6702781840235FF36962688E98C5B" xlink:type="arc" />
    <link:label id="lab_us-gaap_UseOfEstimates_7888A40C898900967E5F962688E928DF_terseLabel_en-US" xlink:label="lab_us-gaap_UseOfEstimates_7888A40C898900967E5F962688E928DF" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Use of Estimates</link:label>
    <link:label id="lab_us-gaap_UseOfEstimates_7888A40C898900967E5F962688E928DF_label_en-US" xlink:label="lab_us-gaap_UseOfEstimates_7888A40C898900967E5F962688E928DF" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Use of Estimates, Policy [Policy Text Block]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_UseOfEstimates" xlink:label="loc_us-gaap_UseOfEstimates_7888A40C898900967E5F962688E928DF" xlink:type="locator" />
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    <link:label id="lab_us-gaap_RevenueRecognitionPolicyTextBlock_75E03B49C68C04E5CB29962688E95C32_terseLabel_en-US" xlink:label="lab_us-gaap_RevenueRecognitionPolicyTextBlock_75E03B49C68C04E5CB29962688E95C32" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Revenue Recognition</link:label>
    <link:label id="lab_us-gaap_RevenueRecognitionPolicyTextBlock_75E03B49C68C04E5CB29962688E95C32_label_en-US" xlink:label="lab_us-gaap_RevenueRecognitionPolicyTextBlock_75E03B49C68C04E5CB29962688E95C32" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenue Recognition, Policy [Policy Text Block]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RevenueRecognitionPolicyTextBlock" xlink:label="loc_us-gaap_RevenueRecognitionPolicyTextBlock_75E03B49C68C04E5CB29962688E95C32" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RevenueRecognitionPolicyTextBlock_75E03B49C68C04E5CB29962688E95C32" xlink:to="lab_us-gaap_RevenueRecognitionPolicyTextBlock_75E03B49C68C04E5CB29962688E95C32" xlink:type="arc" />
    <link:label id="lab_us-gaap_FairValueOfFinancialInstrumentsPolicy_932EED9DDF16092ADBA6962688E90706_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueOfFinancialInstrumentsPolicy_932EED9DDF16092ADBA6962688E90706" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fair Value Measurements</link:label>
    <link:label id="lab_us-gaap_FairValueOfFinancialInstrumentsPolicy_932EED9DDF16092ADBA6962688E90706_label_en-US" xlink:label="lab_us-gaap_FairValueOfFinancialInstrumentsPolicy_932EED9DDF16092ADBA6962688E90706" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value of Financial Instruments, Policy [Policy Text Block]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueOfFinancialInstrumentsPolicy" xlink:label="loc_us-gaap_FairValueOfFinancialInstrumentsPolicy_932EED9DDF16092ADBA6962688E90706" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueOfFinancialInstrumentsPolicy_932EED9DDF16092ADBA6962688E90706" xlink:to="lab_us-gaap_FairValueOfFinancialInstrumentsPolicy_932EED9DDF16092ADBA6962688E90706" xlink:type="arc" />
    <link:label id="lab_us-gaap_CashAndCashEquivalentsPolicyTextBlock_DBD2C06CEFC6146057A9962688EAD03E_terseLabel_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsPolicyTextBlock_DBD2C06CEFC6146057A9962688EAD03E" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash and Cash Equivalents</link:label>
    <link:label id="lab_us-gaap_CashAndCashEquivalentsPolicyTextBlock_DBD2C06CEFC6146057A9962688EAD03E_label_en-US" xlink:label="lab_us-gaap_CashAndCashEquivalentsPolicyTextBlock_DBD2C06CEFC6146057A9962688EAD03E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash and Cash Equivalents, Policy [Policy Text Block]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CashAndCashEquivalentsPolicyTextBlock" xlink:label="loc_us-gaap_CashAndCashEquivalentsPolicyTextBlock_DBD2C06CEFC6146057A9962688EAD03E" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CashAndCashEquivalentsPolicyTextBlock_DBD2C06CEFC6146057A9962688EAD03E" xlink:to="lab_us-gaap_CashAndCashEquivalentsPolicyTextBlock_DBD2C06CEFC6146057A9962688EAD03E" xlink:type="arc" />
    <link:label id="lab_us-gaap_ReceivablesPolicyTextBlock_0D16D5F2212A0571B608962688EA4213_terseLabel_en-US" xlink:label="lab_us-gaap_ReceivablesPolicyTextBlock_0D16D5F2212A0571B608962688EA4213" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accounts Receivable</link:label>
    <link:label id="lab_us-gaap_ReceivablesPolicyTextBlock_0D16D5F2212A0571B608962688EA4213_label_en-US" xlink:label="lab_us-gaap_ReceivablesPolicyTextBlock_0D16D5F2212A0571B608962688EA4213" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Receivables, Policy [Policy Text Block]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ReceivablesPolicyTextBlock" xlink:label="loc_us-gaap_ReceivablesPolicyTextBlock_0D16D5F2212A0571B608962688EA4213" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ReceivablesPolicyTextBlock_0D16D5F2212A0571B608962688EA4213" xlink:to="lab_us-gaap_ReceivablesPolicyTextBlock_0D16D5F2212A0571B608962688EA4213" xlink:type="arc" />
    <link:label id="lab_biib_ConcentrationOfCreditRiskPolicyTextBlock_F47A11A34481216ED881962688EA86DE_terseLabel_en-US" xlink:label="lab_biib_ConcentrationOfCreditRiskPolicyTextBlock_F47A11A34481216ED881962688EA86DE" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Concentration of Credit Risk</link:label>
    <link:label id="lab_biib_ConcentrationOfCreditRiskPolicyTextBlock_F47A11A34481216ED881962688EA86DE_label_en-US" xlink:label="lab_biib_ConcentrationOfCreditRiskPolicyTextBlock_F47A11A34481216ED881962688EA86DE" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Concentration Of Credit Risk [Policy Text Block]</link:label>
    <link:label id="lab_biib_ConcentrationOfCreditRiskPolicyTextBlock_F47A11A34481216ED881962688EA86DE_documentation_en-US" xlink:label="lab_biib_ConcentrationOfCreditRiskPolicyTextBlock_F47A11A34481216ED881962688EA86DE" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Concentration of Credit Risk policy.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_ConcentrationOfCreditRiskPolicyTextBlock" xlink:label="loc_biib_ConcentrationOfCreditRiskPolicyTextBlock_F47A11A34481216ED881962688EA86DE" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_biib_ConcentrationOfCreditRiskPolicyTextBlock_F47A11A34481216ED881962688EA86DE" xlink:to="lab_biib_ConcentrationOfCreditRiskPolicyTextBlock_F47A11A34481216ED881962688EA86DE" xlink:type="arc" />
    <link:label id="lab_us-gaap_InvestmentPolicyTextBlock_4ED3189E029935238DEF962688EA74A0_terseLabel_en-US" xlink:label="lab_us-gaap_InvestmentPolicyTextBlock_4ED3189E029935238DEF962688EA74A0" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Marketable Securities and Other Investments</link:label>
    <link:label id="lab_us-gaap_InvestmentPolicyTextBlock_4ED3189E029935238DEF962688EA74A0_label_en-US" xlink:label="lab_us-gaap_InvestmentPolicyTextBlock_4ED3189E029935238DEF962688EA74A0" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Investment, Policy [Policy Text Block]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InvestmentPolicyTextBlock" xlink:label="loc_us-gaap_InvestmentPolicyTextBlock_4ED3189E029935238DEF962688EA74A0" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InvestmentPolicyTextBlock_4ED3189E029935238DEF962688EA74A0" xlink:to="lab_us-gaap_InvestmentPolicyTextBlock_4ED3189E029935238DEF962688EA74A0" xlink:type="arc" />
    <link:label id="lab_us-gaap_EquityMethodInvestmentsPolicy_B7C238966BE1483EDC0C962688EA95B6_terseLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentsPolicy_B7C238966BE1483EDC0C962688EA95B6" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Equity Method of Accounting</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestmentsPolicy_B7C238966BE1483EDC0C962688EA95B6_label_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentsPolicy_B7C238966BE1483EDC0C962688EA95B6" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investments, Policy [Policy Text Block]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityMethodInvestmentsPolicy" xlink:label="loc_us-gaap_EquityMethodInvestmentsPolicy_B7C238966BE1483EDC0C962688EA95B6" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityMethodInvestmentsPolicy_B7C238966BE1483EDC0C962688EA95B6" xlink:to="lab_us-gaap_EquityMethodInvestmentsPolicy_B7C238966BE1483EDC0C962688EA95B6" xlink:type="arc" />
    <link:label id="lab_us-gaap_InventoryPolicyTextBlock_C51A7F5A287AE730A9F1962688EA073D_terseLabel_en-US" xlink:label="lab_us-gaap_InventoryPolicyTextBlock_C51A7F5A287AE730A9F1962688EA073D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Inventory</link:label>
    <link:label id="lab_us-gaap_InventoryPolicyTextBlock_C51A7F5A287AE730A9F1962688EA073D_label_en-US" xlink:label="lab_us-gaap_InventoryPolicyTextBlock_C51A7F5A287AE730A9F1962688EA073D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Inventory, Policy [Policy Text Block]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InventoryPolicyTextBlock" xlink:label="loc_us-gaap_InventoryPolicyTextBlock_C51A7F5A287AE730A9F1962688EA073D" xlink:type="locator" />
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    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_07E0B9C339BED3DCFA0B962688EAE738_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_07E0B9C339BED3DCFA0B962688EAE738" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_07E0B9C339BED3DCFA0B962688EAE738_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_07E0B9C339BED3DCFA0B962688EAE738" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment, Policy [Policy Text Block]</link:label>
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    <link:label id="lab_biib_IntangibleAssetsAndGoodwillAdditionalTextualAbstract_5E9985E88AC89129E0D31BC9FD82466D_documentation_en-US" xlink:label="lab_biib_IntangibleAssetsAndGoodwillAdditionalTextualAbstract_5E9985E88AC89129E0D31BC9FD82466D" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Intangible assets and goodwill additional.</link:label>
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    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_83EE825ED4C011C365FA1BC9FD823ED7_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_83EE825ED4C011C365FA1BC9FD823ED7" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_83EE825ED4C011C365FA1BC9FD823ED7" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_83EE825ED4C011C365FA1BC9FD823ED7" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_83EE825ED4C011C365FA1BC9FD823ED7" xlink:type="arc" />
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_649A1B69193B216341D71BC9FD82DB73_verboseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_649A1B69193B216341D71BC9FD82DB73" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Expected future amortization expense, 2014</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_649A1B69193B216341D71BC9FD82DB73_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_649A1B69193B216341D71BC9FD82DB73" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets, Amortization Expense, Year Two</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_649A1B69193B216341D71BC9FD82DB73" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_649A1B69193B216341D71BC9FD82DB73" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_649A1B69193B216341D71BC9FD82DB73" xlink:type="arc" />
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_02A1FFF6D1B2926469C11BC9FD8269C3_verboseLabel_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_02A1FFF6D1B2926469C11BC9FD8269C3" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Expected future amortization expense, 2015</link:label>
    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_02A1FFF6D1B2926469C11BC9FD8269C3_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_02A1FFF6D1B2926469C11BC9FD8269C3" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets, Amortization Expense, Year Three</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_02A1FFF6D1B2926469C11BC9FD8269C3" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_02A1FFF6D1B2926469C11BC9FD8269C3" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_02A1FFF6D1B2926469C11BC9FD8269C3" xlink:type="arc" />
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    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_5E31A95B6829939EC8851BC9FD82A4CB_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_5E31A95B6829939EC8851BC9FD82A4CB" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets, Amortization Expense, Year Four</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_5E31A95B6829939EC8851BC9FD82A4CB" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_5E31A95B6829939EC8851BC9FD82A4CB" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_5E31A95B6829939EC8851BC9FD82A4CB" xlink:type="arc" />
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    <link:label id="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_24EADF4F83C47C2292741BC9FD82F834_label_en-US" xlink:label="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_24EADF4F83C47C2292741BC9FD82F834" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Finite-Lived Intangible Assets, Amortization Expense, Year Five</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_24EADF4F83C47C2292741BC9FD82F834" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_24EADF4F83C47C2292741BC9FD82F834" xlink:to="lab_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_24EADF4F83C47C2292741BC9FD82F834" xlink:type="arc" />
    <link:label id="lab_biib_Finitelivedintangibleassetsfutureamortization_99B5BB4CB45E4ACB277E1BD3B6D3E0F6_terseLabel_en-US" xlink:label="lab_biib_Finitelivedintangibleassetsfutureamortization_99B5BB4CB45E4ACB277E1BD3B6D3E0F6" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">FiniteLivedIntangibleAssetsFutureAmortization</link:label>
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    <link:loc xlink:href="biib-20121231.xsd#biib_Finitelivedintangibleassetsfutureamortization" xlink:label="loc_biib_Finitelivedintangibleassetsfutureamortization_99B5BB4CB45E4ACB277E1BD3B6D3E0F6" xlink:type="locator" />
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    <link:label id="lab_us-gaap_StatementOfFinancialPositionAbstract_CB3BAEE4BDF6A4C9D0DB16267374C5CD_label_en-US" xlink:label="lab_us-gaap_StatementOfFinancialPositionAbstract_CB3BAEE4BDF6A4C9D0DB16267374C5CD" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statement of Financial Position [Abstract]</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockParOrStatedValuePerShare" xlink:label="loc_us-gaap_PreferredStockParOrStatedValuePerShare_49D63E24EB5F0B74D7A11626737440D9" xlink:type="locator" />
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    <link:label id="lab_us-gaap_MachineryAndEquipmentMember_93E396693142B03201FA1626734EDC71_terseLabel_en-US" xlink:label="lab_us-gaap_MachineryAndEquipmentMember_93E396693142B03201FA1626734EDC71" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Machinery and Equipment</link:label>
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    <link:label id="lab_us-gaap_ComputerEquipmentMember_760C8A910685CE2837531626734E3058_terseLabel_en-US" xlink:label="lab_us-gaap_ComputerEquipmentMember_760C8A910685CE2837531626734E3058" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Computer Equipment</link:label>
    <link:label id="lab_us-gaap_ComputerEquipmentMember_760C8A910685CE2837531626734E3058_label_en-US" xlink:label="lab_us-gaap_ComputerEquipmentMember_760C8A910685CE2837531626734E3058" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Computer Equipment [Member]</link:label>
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    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentLineItems_3490A1A88D84F742C54F1626734EB1B5_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentLineItems_3490A1A88D84F742C54F1626734EB1B5" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentLineItems_3490A1A88D84F742C54F1626734EB1B5_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentLineItems_3490A1A88D84F742C54F1626734EB1B5" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment [Line Items]</link:label>
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    <link:label id="lab_biib_BusinessTextualAbstract_B4C615494D43818770AF1626734E1B0D_terseLabel_en-US" xlink:label="lab_biib_BusinessTextualAbstract_B4C615494D43818770AF1626734E1B0D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Business (Textual)</link:label>
    <link:label id="lab_biib_BusinessTextualAbstract_B4C615494D43818770AF1626734E1B0D_label_en-US" xlink:label="lab_biib_BusinessTextualAbstract_B4C615494D43818770AF1626734E1B0D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business (Textual) [Abstract]</link:label>
    <link:label id="lab_biib_BusinessTextualAbstract_B4C615494D43818770AF1626734E1B0D_documentation_en-US" xlink:label="lab_biib_BusinessTextualAbstract_B4C615494D43818770AF1626734E1B0D" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Business.</link:label>
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    <link:label id="lab_biib_InterestInSubsidiary_57FAC4F99D1DEEA94D651626734EE123_terseLabel_en-US" xlink:label="lab_biib_InterestInSubsidiary_57FAC4F99D1DEEA94D651626734EE123" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest in subsidiary (less than given percentage)</link:label>
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    <link:label id="lab_biib_InterestInSubsidiary_57FAC4F99D1DEEA94D651626734EE123_documentation_en-US" xlink:label="lab_biib_InterestInSubsidiary_57FAC4F99D1DEEA94D651626734EE123" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Interest in subsidiary.</link:label>
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    <link:label id="lab_biib_PaymentTermsOfAccountsReceivable_4C5E23E86151C487CCFC1626734E1F43_verboseLabel_en-US" xlink:label="lab_biib_PaymentTermsOfAccountsReceivable_4C5E23E86151C487CCFC1626734E1F43" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Payment terms of accounts receivable arising from product sales</link:label>
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    <link:loc xlink:href="biib-20121231.xsd#biib_PaymentTermsOfAccountsReceivable" xlink:label="loc_biib_PaymentTermsOfAccountsReceivable_4C5E23E86151C487CCFC1626734E1F43" xlink:type="locator" />
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    <link:label id="lab_biib_PercentageReceivablesOfWholesaleDistributorAccountedInConsolidatedReceivables_9BDC47C444390D92CFEA1626734E3424_terseLabel_en-US" xlink:label="lab_biib_PercentageReceivablesOfWholesaleDistributorAccountedInConsolidatedReceivables_9BDC47C444390D92CFEA1626734E3424" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Percentage receivables of wholesale distributor accounted in consolidated receivables</link:label>
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    <link:label id="lab_biib_PercentageReceivablesOfWholesaleDistributorAccountedInConsolidatedReceivables_9BDC47C444390D92CFEA1626734E3424_documentation_en-US" xlink:label="lab_biib_PercentageReceivablesOfWholesaleDistributorAccountedInConsolidatedReceivables_9BDC47C444390D92CFEA1626734E3424" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Percentage receivables of wholesale distributor accounted in consolidated receivables.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_PercentageReceivablesOfWholesaleDistributorAccountedInConsolidatedReceivables" xlink:label="loc_biib_PercentageReceivablesOfWholesaleDistributorAccountedInConsolidatedReceivables_9BDC47C444390D92CFEA1626734E3424" xlink:type="locator" />
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    <link:label id="lab_biib_EstimatedUsefulLivesOfLeaseholdImprovements_CC1A78A6DD6D5466845D1626734EDD2C_terseLabel_en-US" xlink:label="lab_biib_EstimatedUsefulLivesOfLeaseholdImprovements_CC1A78A6DD6D5466845D1626734EDD2C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Estimated useful lives of leasehold improvements</link:label>
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    <link:label id="lab_biib_EstimatedUsefulLivesOfLeaseholdImprovements_CC1A78A6DD6D5466845D1626734EDD2C_documentation_en-US" xlink:label="lab_biib_EstimatedUsefulLivesOfLeaseholdImprovements_CC1A78A6DD6D5466845D1626734EDD2C" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Estimated useful lives of leasehold improvements.</link:label>
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    <link:label id="lab_biib_PurchasePriceOfCommonStockUnderEspp_1FB6CB62D66A9B3A429D1626734EE2E7_terseLabel_en-US" xlink:label="lab_biib_PurchasePriceOfCommonStockUnderEspp_1FB6CB62D66A9B3A429D1626734EE2E7" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Purchase price of common stock under ESPP</link:label>
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    <link:label id="lab_biib_PercentageOfMarketValuePerShareOfCommonStock_04B4E9C5934CE20C289C1626734EAE5F_terseLabel_en-US" xlink:label="lab_biib_PercentageOfMarketValuePerShareOfCommonStock_04B4E9C5934CE20C289C1626734EAE5F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Percentage of market value per share of common stock</link:label>
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    <link:label id="lab_biib_CompensationExpenseOverPurchasePeriod_C276944E95B318B6468D1626734EAD82_terseLabel_en-US" xlink:label="lab_biib_CompensationExpenseOverPurchasePeriod_C276944E95B318B6468D1626734EAD82" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Compensation expense over purchase period</link:label>
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    <link:label id="lab_biib_CompensationExpenseOverPurchasePeriod_C276944E95B318B6468D1626734EAD82_documentation_en-US" xlink:label="lab_biib_CompensationExpenseOverPurchasePeriod_C276944E95B318B6468D1626734EAD82" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Compensation expense over purchase period.</link:label>
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    <link:label id="lab_biib_DiscountRateRecognizedInCompensationExpense_040F68F1E2078C569DF41626734EFFFD_terseLabel_en-US" xlink:label="lab_biib_DiscountRateRecognizedInCompensationExpense_040F68F1E2078C569DF41626734EFFFD" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Discount rate recognized in compensation expense</link:label>
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    <link:label id="lab_us-gaap_BusinessAcquisitionLineItems_F63DBBBDB5F9C269B99B1BDA4B09D0E0_verboseLabel_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionLineItems_F63DBBBDB5F9C269B99B1BDA4B09D0E0" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Purchase price allocation for the acquisition</link:label>
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    <link:label id="lab_biib_BusinessAcquisitionCostOfAcquiredEntityFairValueOfPreExistingEquityOwnership_27F2CFBF35B3E39347D51BDA4B09D22F_terseLabel_en-US" xlink:label="lab_biib_BusinessAcquisitionCostOfAcquiredEntityFairValueOfPreExistingEquityOwnership_27F2CFBF35B3E39347D51BDA4B09D22F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fair value of pre-existing equity ownership</link:label>
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    <link:label id="lab_biib_BusinessAcquisitionCostOfAcquiredEntityFairValueOfPreExistingEquityOwnership_27F2CFBF35B3E39347D51BDA4B09D22F_documentation_en-US" xlink:label="lab_biib_BusinessAcquisitionCostOfAcquiredEntityFairValueOfPreExistingEquityOwnership_27F2CFBF35B3E39347D51BDA4B09D22F" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Business acquisition cost of acquired entity fair value of pre-existing equity ownership.</link:label>
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    <link:label id="lab_us-gaap_BusinessAcquisitionCostOfAcquiredEntityPurchasePrice_B591388478CD72A5C9C61BDA4B090CA9_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionCostOfAcquiredEntityPurchasePrice_B591388478CD72A5C9C61BDA4B090CA9" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total purchase price</link:label>
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    <link:label id="lab_country_DK_A6FD398218AD852A8CE7D8B585A2B2D3_terseLabel_en-US" xlink:label="lab_country_DK_A6FD398218AD852A8CE7D8B585A2B2D3" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">DENMARK</link:label>
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    <link:loc xlink:href="biib-20121231.xsd#biib_MajorDistributorAxis" xlink:label="loc_biib_MajorDistributorAxis_537B6C871165DF8F79D8D8B585A2A59C" xlink:type="locator" />
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    <link:label id="lab_us-gaap_StatementOfCashFlowsAbstract_26A10FF0B520AE8BB723962688FB0D20_label_en-US" xlink:label="lab_us-gaap_StatementOfCashFlowsAbstract_26A10FF0B520AE8BB723962688FB0D20" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statement of Cash Flows [Abstract]</link:label>
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    <link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_361E0DD6C891456E1CF5962688FB8854_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_361E0DD6C891456E1CF5962688FB8854" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Cash Provided by (Used in) Operating Activities [Abstract]</link:label>
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    <link:label id="lab_us-gaap_ResearchAndDevelopmentInProcess_040188ED73D500EFBD73962688FB3F11_label_en-US" xlink:label="lab_us-gaap_ResearchAndDevelopmentInProcess_040188ED73D500EFBD73962688FB3F11" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Research and Development in Process</link:label>
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    <link:label id="lab_us-gaap_ShareBasedCompensation_F9356282103F43FB3ACA962688FB742D_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensation_F9356282103F43FB3ACA962688FB742D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation</link:label>
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    <link:label id="lab_biib_FairValueAdjustmentOfContingentConsideration_F311FA56468D4B0F43D3962688FBC47E_verboseLabel_en-US" xlink:label="lab_biib_FairValueAdjustmentOfContingentConsideration_F311FA56468D4B0F43D3962688FBC47E" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Fair value adjustment of contingent consideration</link:label>
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    <link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_E5CF8E729973AA091E70962688FCF2B6_verboseLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_E5CF8E729973AA091E70962688FCF2B6" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Cash flows from investing activities:</link:label>
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    <link:label id="lab_us-gaap_PaymentsForRepurchaseOfCommonStock_CF17ED6D5DC1E6CB4ECC962688FD48E6_negatedLabel_en-US" xlink:label="lab_us-gaap_PaymentsForRepurchaseOfCommonStock_CF17ED6D5DC1E6CB4ECC962688FD48E6" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Purchase of treasury stock</link:label>
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    <link:label id="lab_us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlans_3FD30B9E06BF36E4EA0C962688FDB7B3_verboseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlans_3FD30B9E06BF36E4EA0C962688FDB7B3" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from issuance of stock for share-based compensation arrangements</link:label>
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    <link:label id="lab_biib_PaymentsForAcquisitionOfNoncontrollingInterest_1B89EFDA947E5207D79D962688FDA167_negatedTerseLabel_en-US" xlink:label="lab_biib_PaymentsForAcquisitionOfNoncontrollingInterest_1B89EFDA947E5207D79D962688FDA167" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Acquisition of noncontrolling interests</link:label>
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    <link:label id="lab_us-gaap_PaymentsToMinorityShareholders_E5AFA302B1C8E7C0B2DC962688FD6A4E_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_PaymentsToMinorityShareholders_E5AFA302B1C8E7C0B2DC962688FD6A4E" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Net distributions to noncontrolling interests</link:label>
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    <link:label id="lab_us-gaap_RepaymentsOfShortTermDebt_B3D12018E697EE529822962688FDEBBF_label_en-US" xlink:label="lab_us-gaap_RepaymentsOfShortTermDebt_B3D12018E697EE529822962688FDEBBF" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Repayments of Short-term Debt</link:label>
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    <link:label id="lab_biib_BusinessAcquisitionContingentConsiderationCashPayment_CFF5DC6D65DF0643925B962688FD5E10_negatedTerseLabel_en-US" xlink:label="lab_biib_BusinessAcquisitionContingentConsiderationCashPayment_CFF5DC6D65DF0643925B962688FD5E10" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Cash payments for contingent consideration</link:label>
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    <link:label id="lab_biib_NetProceedsFromFinancingArrangementForSaleOfFacility_1341E18334AC6D33042F962688FDC3EC_terseLabel_en-US" xlink:label="lab_biib_NetProceedsFromFinancingArrangementForSaleOfFacility_1341E18334AC6D33042F962688FDC3EC" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net proceeds from financing arrangement for the sale of the San Diego facility</link:label>
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    <link:label id="lab_biib_VpOneProteinMember_20CABDA29958B23F25E9B0317B477B8B_terseLabel_en-US" xlink:label="lab_biib_VpOneProteinMember_20CABDA29958B23F25E9B0317B477B8B" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">VP One Protein</link:label>
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    <link:label id="lab_biib_RemainingPotentialDevelopmentMilestonePaymentsAndRoyaltiesOnCommercialSalesUnderTermsOfCollaborationAgreement_0BC8A8A8677F7B033990B0317B47F6FE_terseLabel_en-US" xlink:label="lab_biib_RemainingPotentialDevelopmentMilestonePaymentsAndRoyaltiesOnCommercialSalesUnderTermsOfCollaborationAgreement_0BC8A8A8677F7B033990B0317B47F6FE" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Expected usage-based royalties to be earned through 2016 from license agreement</link:label>
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    <link:loc xlink:href="biib-20121231.xsd#biib_RemainingPotentialDevelopmentMilestonePaymentsAndRoyaltiesOnCommercialSalesUnderTermsOfCollaborationAgreement" xlink:label="loc_biib_RemainingPotentialDevelopmentMilestonePaymentsAndRoyaltiesOnCommercialSalesUnderTermsOfCollaborationAgreement_0BC8A8A8677F7B033990B0317B47F6FE" xlink:type="locator" />
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    <link:label id="lab_biib_IntangibleAssetsGrossExcludingGoodwill_815A386D67918C5C09D0B0317B486514_verboseLabel_en-US" xlink:label="lab_biib_IntangibleAssetsGrossExcludingGoodwill_815A386D67918C5C09D0B0317B486514" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Intangible asset recognized to reflect the total of upfront and other time-based milestone payments expected to be made</link:label>
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    <link:label id="lab_biib_MilestonesPaymentsMadeToCollaborativePartners_03425D8B01EB96AF5F4DB08290064CA2_terseLabel_en-US" xlink:label="lab_biib_MilestonesPaymentsMadeToCollaborativePartners_03425D8B01EB96AF5F4DB08290064CA2" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total milestone payments</link:label>
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    <link:label id="lab_biib_ExpectedAdditionalMilestonePaymentsWhenMeetingCertainSalesThreshold_7CD3BA5596A7FD3F82F8B082903A1192_verboseLabel_en-US" xlink:label="lab_biib_ExpectedAdditionalMilestonePaymentsWhenMeetingCertainSalesThreshold_7CD3BA5596A7FD3F82F8B082903A1192" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Expected additional milestone payments when certain sales threshold is met</link:label>
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    <link:label id="lab_biib_ForeignSalesRequiredToTriggerMilestone_18E5DD2683A1CF53DBD5B0829072F7B1_verboseLabel_en-US" xlink:label="lab_biib_ForeignSalesRequiredToTriggerMilestone_18E5DD2683A1CF53DBD5B0829072F7B1" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Foreign sales required to trigger milestone</link:label>
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    <link:label id="lab_us-gaap_GoodwillImpairedAccumulatedImpairmentLoss_2832063CB4C75A38AACCB073777D4D87_terseLabel_en-US" xlink:label="lab_us-gaap_GoodwillImpairedAccumulatedImpairmentLoss_2832063CB4C75A38AACCB073777D4D87" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accumulated impairment losses related to goodwill</link:label>
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    <link:label id="lab_biib_SharesIssuedUnderEmployeeStockPurchasePlanAbstract_E3BE970DA3A615893DCE96DC1B2ECAD4_verboseLabel_en-US" xlink:label="lab_biib_SharesIssuedUnderEmployeeStockPurchasePlanAbstract_E3BE970DA3A615893DCE96DC1B2ECAD4" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Shares issued under employee stock purchase plan</link:label>
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    <link:label id="lab_us-gaap_LongTermDebtByMaturityAbstract_D90D14F5D6FB1D62F4E767C9121432DC_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtByMaturityAbstract_D90D14F5D6FB1D62F4E767C9121432DC" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total debt maturities</link:label>
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    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_01156BCA9C6B56EEBD5967C912143FCE_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_01156BCA9C6B56EEBD5967C912143FCE" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2013</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_01156BCA9C6B56EEBD5967C912143FCE" xlink:type="locator" />
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    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_8687008D6B3E3FE9388B67C91214473B_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_8687008D6B3E3FE9388B67C91214473B" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2014</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_8687008D6B3E3FE9388B67C91214473B" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_8687008D6B3E3FE9388B67C91214473B" xlink:to="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_8687008D6B3E3FE9388B67C91214473B" xlink:type="arc" />
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_9744ACED93D50919990A67C9121461D5_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_9744ACED93D50919990A67C9121461D5" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2015</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_9744ACED93D50919990A67C9121461D5" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_9744ACED93D50919990A67C9121461D5" xlink:to="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_9744ACED93D50919990A67C9121461D5" xlink:type="arc" />
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_257C3DA285729524A87067C912140D09_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_257C3DA285729524A87067C912140D09" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2016</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_257C3DA285729524A87067C912140D09" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_257C3DA285729524A87067C912140D09" xlink:to="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_257C3DA285729524A87067C912140D09" xlink:type="arc" />
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive_CAE9D0391AC0FB95707267C91219A56A_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive_CAE9D0391AC0FB95707267C91219A56A" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2017</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive_CAE9D0391AC0FB95707267C91219A56A" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive_CAE9D0391AC0FB95707267C91219A56A" xlink:to="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive_CAE9D0391AC0FB95707267C91219A56A" xlink:type="arc" />
    <link:label id="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive_99798D864B446718F46767C91219333C_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive_99798D864B446718F46767C91219333C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">2018 and thereafter</link:label>
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    <link:label id="lab_us-gaap_LongTermDebt_A5413888BEAE2635413567C9121ADCF9_totalLabel_en-US" xlink:label="lab_us-gaap_LongTermDebt_A5413888BEAE2635413567C9121ADCF9" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total</link:label>
    <link:label id="lab_us-gaap_LongTermDebt_A5413888BEAE2635413567C9121ADCF9_label_en-US" xlink:label="lab_us-gaap_LongTermDebt_A5413888BEAE2635413567C9121ADCF9" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-term Debt</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LongTermDebt" xlink:label="loc_us-gaap_LongTermDebt_A5413888BEAE2635413567C9121ADCF9" xlink:type="locator" />
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    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_5D20D310C7BF2229818496DC2EE6D7F1_verboseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract_5D20D310C7BF2229818496DC2EE6D7F1" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Weighted-average assumptions to estimate the fair value of the stock option grants awarded</link:label>
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    <link:label id="lab_biib_CollaborationsTextualAbstract_CF1A0416AB7CEBBDBBF28E22AA8D3E5E_verboseLabel_en-US" xlink:label="lab_biib_CollaborationsTextualAbstract_CF1A0416AB7CEBBDBBF28E22AA8D3E5E" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Collaborative and Other Relationships (Textual)</link:label>
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    <link:label id="lab_biib_FutureRoyaltiesPercentageToBeReceivedOnSaleOfProduct_4D478F7C39FC090292D98E22AA8D4831_documentation_en-US" xlink:label="lab_biib_FutureRoyaltiesPercentageToBeReceivedOnSaleOfProduct_4D478F7C39FC090292D98E22AA8D4831" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Future royalties percentage to be received on sale of product.</link:label>
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    <link:label id="lab_biib_PercentageOfFutureDevelopmentAndCommercializationExpensesPayableRelated_93936F6E96A0465FCBE78E22AA8D0F4B_verboseLabel_en-US" xlink:label="lab_biib_PercentageOfFutureDevelopmentAndCommercializationExpensesPayableRelated_93936F6E96A0465FCBE78E22AA8D0F4B" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Percentage of future development and commercialization expenses payable related to GA101</link:label>
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    <link:label id="lab_biib_PercentageOfFutureDevelopmentAndCommercializationExpensesPayableRelated_93936F6E96A0465FCBE78E22AA8D0F4B_documentation_en-US" xlink:label="lab_biib_PercentageOfFutureDevelopmentAndCommercializationExpensesPayableRelated_93936F6E96A0465FCBE78E22AA8D0F4B" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Percentage of future development and commercialization expenses payable related.</link:label>
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    <link:label id="lab_biib_ProfitSharingOnSaleOfProductPercentage_D5BACE79EE45FB4C971F8E22AA8E0431_verboseLabel_en-US" xlink:label="lab_biib_ProfitSharingOnSaleOfProductPercentage_D5BACE79EE45FB4C971F8E22AA8E0431" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Profit sharing on sale of GA 101, percentage</link:label>
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    <link:label id="lab_biib_RateDuringReimbursementPeriod_46160A69F35A2F60A5820B52645F8707_label_en-US" xlink:label="lab_biib_RateDuringReimbursementPeriod_46160A69F35A2F60A5820B52645F8707" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Rate During Reimbursement Period</link:label>
    <link:label id="lab_biib_RateDuringReimbursementPeriod_46160A69F35A2F60A5820B52645F8707_documentation_en-US" xlink:label="lab_biib_RateDuringReimbursementPeriod_46160A69F35A2F60A5820B52645F8707" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Rate during the reimbursement period.</link:label>
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    <link:label id="lab_biib_NotesPayableToFumedicaMember_F776E90E4C040A84494D96F5004427B1_label_en-US" xlink:label="lab_biib_NotesPayableToFumedicaMember_F776E90E4C040A84494D96F5004427B1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Notes Payable To Fumedica [Member]</link:label>
    <link:label id="lab_biib_NotesPayableToFumedicaMember_F776E90E4C040A84494D96F5004427B1_documentation_en-US" xlink:label="lab_biib_NotesPayableToFumedicaMember_F776E90E4C040A84494D96F5004427B1" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Notes payable.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_NotesPayableToFumedicaMember" xlink:label="loc_biib_NotesPayableToFumedicaMember_F776E90E4C040A84494D96F5004427B1" xlink:type="locator" />
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    <link:label id="lab_biib_SummaryOfFairAndCarryingValueOfDebtInstrumentsAbstract_5492425A0B33EC89E00496F50044A561_documentation_en-US" xlink:label="lab_biib_SummaryOfFairAndCarryingValueOfDebtInstrumentsAbstract_5492425A0B33EC89E00496F50044A561" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Summary of fair and carrying value of debt instruments.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_SummaryOfFairAndCarryingValueOfDebtInstrumentsAbstract" xlink:label="loc_biib_SummaryOfFairAndCarryingValueOfDebtInstrumentsAbstract_5492425A0B33EC89E00496F50044A561" xlink:type="locator" />
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    <link:label id="lab_us-gaap_NotesPayableFairValueDisclosure_8368BE56016FB29AE8B096F500447096_label_en-US" xlink:label="lab_us-gaap_NotesPayableFairValueDisclosure_8368BE56016FB29AE8B096F500447096" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Notes Payable, Fair Value Disclosure</link:label>
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    <link:label id="lab_us-gaap_DebtInstrumentFairValue_331FE3FA0B575270C4BB96F500443C16_verboseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentFairValue_331FE3FA0B575270C4BB96F500443C16" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Total fair value</link:label>
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    <link:label id="lab_biib_ComponentsOfInventoryTable_94A686D0706D5839A93F49ADE0DA6EED_terseLabel_en-US" xlink:label="lab_biib_ComponentsOfInventoryTable_94A686D0706D5839A93F49ADE0DA6EED" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Components of inventory [Table]</link:label>
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    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_biib_TysabriMember_5E4933B44DB4B32924F549ADE0DA667A" xlink:to="lab_biib_TysabriMember_5E4933B44DB4B32924F549ADE0DA667A" xlink:type="arc" />
    <link:label id="lab_biib_OtherProductsMember_66CFB81276F67338218249ADE0DA9034_terseLabel_en-US" xlink:label="lab_biib_OtherProductsMember_66CFB81276F67338218249ADE0DA9034" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other</link:label>
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    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_biib_OtherProductsMember_66CFB81276F67338218249ADE0DA9034" xlink:to="lab_biib_OtherProductsMember_66CFB81276F67338218249ADE0DA9034" xlink:type="arc" />
    <link:label id="lab_biib_ComponentsOfInventoryLineItems_C9767BD2F73BBF2EA9E649ADE0DA88E8_terseLabel_en-US" xlink:label="lab_biib_ComponentsOfInventoryLineItems_C9767BD2F73BBF2EA9E649ADE0DA88E8" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Components of inventory</link:label>
    <link:label id="lab_biib_ComponentsOfInventoryLineItems_C9767BD2F73BBF2EA9E649ADE0DA88E8_label_en-US" xlink:label="lab_biib_ComponentsOfInventoryLineItems_C9767BD2F73BBF2EA9E649ADE0DA88E8" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Components of inventory [Line Items]</link:label>
    <link:label id="lab_biib_ComponentsOfInventoryLineItems_C9767BD2F73BBF2EA9E649ADE0DA88E8_documentation_en-US" xlink:label="lab_biib_ComponentsOfInventoryLineItems_C9767BD2F73BBF2EA9E649ADE0DA88E8" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Components of inventory.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_ComponentsOfInventoryLineItems" xlink:label="loc_biib_ComponentsOfInventoryLineItems_C9767BD2F73BBF2EA9E649ADE0DA88E8" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_biib_ComponentsOfInventoryLineItems_C9767BD2F73BBF2EA9E649ADE0DA88E8" xlink:to="lab_biib_ComponentsOfInventoryLineItems_C9767BD2F73BBF2EA9E649ADE0DA88E8" xlink:type="arc" />
    <link:label id="lab_us-gaap_InventoryFinishedGoodsAndWorkInProcess_6426D8015675E4AFE60449ADE0DA19B9_terseLabel_en-US" xlink:label="lab_us-gaap_InventoryFinishedGoodsAndWorkInProcess_6426D8015675E4AFE60449ADE0DA19B9" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total finished goods and work in process</link:label>
    <link:label id="lab_us-gaap_InventoryFinishedGoodsAndWorkInProcess_6426D8015675E4AFE60449ADE0DA19B9_label_en-US" xlink:label="lab_us-gaap_InventoryFinishedGoodsAndWorkInProcess_6426D8015675E4AFE60449ADE0DA19B9" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Inventory, Finished Goods and Work in Process, Gross</link:label>
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    <link:label id="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax_B6E8ED1BAE19A5B9F9EF622B6BD8E297_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossDefinedBenefitPensionAndOtherPostretirementPlansNetOfTax_B6E8ED1BAE19A5B9F9EF622B6BD8E297" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Unfunded status of pension and postretirement benefit plans</link:label>
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    <link:label id="lab_biib_WestonFacilityMember_6E929DC91B596EB559ED5E0954C45977_terseLabel_en-US" xlink:label="lab_biib_WestonFacilityMember_6E929DC91B596EB559ED5E0954C45977" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Weston Facility</link:label>
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    <link:label id="lab_biib_EisaiMember_70FB108912F187FC5EBD5E7C9D98770C_terseLabel_en-US" xlink:label="lab_biib_EisaiMember_70FB108912F187FC5EBD5E7C9D98770C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Eisai [Member]</link:label>
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    <link:label id="lab_biib_FumadermAndBgTwelveMember_1B92997970161A2663155E0954C577CC_verboseLabel_en-US" xlink:label="lab_biib_FumadermAndBgTwelveMember_1B92997970161A2663155E0954C577CC" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">FUMADERM and BG-12</link:label>
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    <link:loc xlink:href="biib-20121231.xsd#biib_FumadermAndBgTwelveMember" xlink:label="loc_biib_FumadermAndBgTwelveMember_1B92997970161A2663155E0954C577CC" xlink:type="locator" />
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    <link:label id="lab_biib_TermOfLease_28B7F68A9A364477831F5E0954C5E21D_verboseLabel_en-US" xlink:label="lab_biib_TermOfLease_28B7F68A9A364477831F5E0954C5E21D" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Sale Leaseback Transaction Period In Years</link:label>
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    <link:loc xlink:href="biib-20121231.xsd#biib_TermOfLease" xlink:label="loc_biib_TermOfLease_28B7F68A9A364477831F5E0954C5E21D" xlink:type="locator" />
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    <link:label id="lab_biib_BusinessAcquisitionCostOfAcquiredEntityAdditionalContingentConsiderationAssociatedWithApprovalOfLicenseApplication_723FAF72FACF4053D9995E0954C50DD4_verboseLabel_en-US" xlink:label="lab_biib_BusinessAcquisitionCostOfAcquiredEntityAdditionalContingentConsiderationAssociatedWithApprovalOfLicenseApplication_723FAF72FACF4053D9995E0954C50DD4" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Additional contingent payment for Biologic License</link:label>
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    <link:label id="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_E0FD8C85CD4284D0B9605E0954CC22DD_verboseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_E0FD8C85CD4284D0B9605E0954CC22DD" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Minimum lease payments, 2016</link:label>
    <link:label id="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_E0FD8C85CD4284D0B9605E0954CC22DD_label_en-US" xlink:label="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_E0FD8C85CD4284D0B9605E0954CC22DD" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Leases, Future Minimum Payments, Due in Four Years</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_E0FD8C85CD4284D0B9605E0954CC22DD" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_E0FD8C85CD4284D0B9605E0954CC22DD" xlink:to="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_E0FD8C85CD4284D0B9605E0954CC22DD" xlink:type="arc" />
    <link:label id="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears_448339C5A6CBE150DE2B5E0954CC008B_verboseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears_448339C5A6CBE150DE2B5E0954CC008B" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Minimum lease payments, 2017</link:label>
    <link:label id="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears_448339C5A6CBE150DE2B5E0954CC008B_label_en-US" xlink:label="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears_448339C5A6CBE150DE2B5E0954CC008B" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Leases, Future Minimum Payments, Due in Five Years</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears_448339C5A6CBE150DE2B5E0954CC008B" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears_448339C5A6CBE150DE2B5E0954CC008B" xlink:to="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears_448339C5A6CBE150DE2B5E0954CC008B" xlink:type="arc" />
    <link:label id="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter_1A5D6C6A6EDD85C4A7405E0954CC9055_verboseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter_1A5D6C6A6EDD85C4A7405E0954CC9055" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Minimum lease payments, Thereafter</link:label>
    <link:label id="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter_1A5D6C6A6EDD85C4A7405E0954CC9055_label_en-US" xlink:label="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter_1A5D6C6A6EDD85C4A7405E0954CC9055" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Leases, Future Minimum Payments, Due Thereafter</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter_1A5D6C6A6EDD85C4A7405E0954CC9055" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter_1A5D6C6A6EDD85C4A7405E0954CC9055" xlink:to="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter_1A5D6C6A6EDD85C4A7405E0954CC9055" xlink:type="arc" />
    <link:label id="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDue_571EA35BFF65E2C93ECE5E0954CC567D_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDue_571EA35BFF65E2C93ECE5E0954CC567D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Minimum lease payments, Total</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:label="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDue_571EA35BFF65E2C93ECE5E0954CC567D" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeasesFutureMinimumPaymentsDue_571EA35BFF65E2C93ECE5E0954CC567D" xlink:to="lab_us-gaap_OperatingLeasesFutureMinimumPaymentsDue_571EA35BFF65E2C93ECE5E0954CC567D" xlink:type="arc" />
    <link:label id="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinOneYear_FB83256282486E5AFDE05E0954CC1A96_negatedLabel_en-US" xlink:label="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinOneYear_FB83256282486E5AFDE05E0954CC1A96" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Less: income from subleases, 2013</link:label>
    <link:label id="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinOneYear_FB83256282486E5AFDE05E0954CC1A96_label_en-US" xlink:label="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinOneYear_FB83256282486E5AFDE05E0954CC1A96" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Future Minimum Sublease Rentals, Sale Leaseback Transactions, Next Twelve Months</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinOneYear" xlink:label="loc_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinOneYear_FB83256282486E5AFDE05E0954CC1A96" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinOneYear_FB83256282486E5AFDE05E0954CC1A96" xlink:to="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinOneYear_FB83256282486E5AFDE05E0954CC1A96" xlink:type="arc" />
    <link:label id="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinTwoYears_9A5E72CB97229201BCBA5E0954CD5362_negatedLabel_en-US" xlink:label="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinTwoYears_9A5E72CB97229201BCBA5E0954CD5362" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Less: income from subleases, 2014</link:label>
    <link:label id="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinTwoYears_9A5E72CB97229201BCBA5E0954CD5362_label_en-US" xlink:label="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinTwoYears_9A5E72CB97229201BCBA5E0954CD5362" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Future Minimum Sublease Rentals, Sale Leaseback Transactions, within Two Years</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinTwoYears" xlink:label="loc_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinTwoYears_9A5E72CB97229201BCBA5E0954CD5362" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinTwoYears_9A5E72CB97229201BCBA5E0954CD5362" xlink:to="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinTwoYears_9A5E72CB97229201BCBA5E0954CD5362" xlink:type="arc" />
    <link:label id="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinThreeYears_3990618BBED2843755375E0954CD6649_negatedLabel_en-US" xlink:label="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinThreeYears_3990618BBED2843755375E0954CD6649" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Less: income from subleases, 2015</link:label>
    <link:label id="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinThreeYears_3990618BBED2843755375E0954CD6649_label_en-US" xlink:label="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinThreeYears_3990618BBED2843755375E0954CD6649" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Future Minimum Sublease Rentals, Sale Leaseback Transactions, within Three Years</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinThreeYears" xlink:label="loc_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinThreeYears_3990618BBED2843755375E0954CD6649" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinThreeYears_3990618BBED2843755375E0954CD6649" xlink:to="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinThreeYears_3990618BBED2843755375E0954CD6649" xlink:type="arc" />
    <link:label id="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinFourYears_4F95C761DD661179939A5E0954CDDD24_negatedLabel_en-US" xlink:label="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinFourYears_4F95C761DD661179939A5E0954CDDD24" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Less: income from subleases, 2016</link:label>
    <link:label id="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinFourYears_4F95C761DD661179939A5E0954CDDD24_label_en-US" xlink:label="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinFourYears_4F95C761DD661179939A5E0954CDDD24" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Future Minimum Sublease Rentals, Sale Leaseback Transactions, within Four Years</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinFourYears" xlink:label="loc_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinFourYears_4F95C761DD661179939A5E0954CDDD24" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinFourYears_4F95C761DD661179939A5E0954CDDD24" xlink:to="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinFourYears_4F95C761DD661179939A5E0954CDDD24" xlink:type="arc" />
    <link:label id="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinFiveYears_08F864D4ECF7D40772275E0954CD46F7_negatedLabel_en-US" xlink:label="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinFiveYears_08F864D4ECF7D40772275E0954CD46F7" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Less: income from subleases, 2017</link:label>
    <link:label id="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinFiveYears_08F864D4ECF7D40772275E0954CD46F7_label_en-US" xlink:label="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinFiveYears_08F864D4ECF7D40772275E0954CD46F7" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Future Minimum Sublease Rentals, Sale Leaseback Transactions, within Five Years</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinFiveYears" xlink:label="loc_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinFiveYears_08F864D4ECF7D40772275E0954CD46F7" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinFiveYears_08F864D4ECF7D40772275E0954CD46F7" xlink:to="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsWithinFiveYears_08F864D4ECF7D40772275E0954CD46F7" xlink:type="arc" />
    <link:label id="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsThereafter_25D9665B85B6E25E3BB95E0954CDC4C7_negatedLabel_en-US" xlink:label="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsThereafter_25D9665B85B6E25E3BB95E0954CDC4C7" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Less: income from subleases, Thereafter</link:label>
    <link:label id="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsThereafter_25D9665B85B6E25E3BB95E0954CDC4C7_label_en-US" xlink:label="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsThereafter_25D9665B85B6E25E3BB95E0954CDC4C7" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Future Minimum Sublease Rentals, Sale Leaseback Transactions, Thereafter</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsThereafter" xlink:label="loc_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsThereafter_25D9665B85B6E25E3BB95E0954CDC4C7" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsThereafter_25D9665B85B6E25E3BB95E0954CDC4C7" xlink:to="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactionsThereafter_25D9665B85B6E25E3BB95E0954CDC4C7" xlink:type="arc" />
    <link:label id="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactions_47CA9EF155F52CF87A615E0954CDFC8D_negatedLabel_en-US" xlink:label="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactions_47CA9EF155F52CF87A615E0954CDFC8D" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Less: income from subleases, Total</link:label>
    <link:label id="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactions_47CA9EF155F52CF87A615E0954CDFC8D_label_en-US" xlink:label="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactions_47CA9EF155F52CF87A615E0954CDFC8D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Future Minimum Sublease Rentals, Sale Leaseback Transactions</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactions" xlink:label="loc_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactions_47CA9EF155F52CF87A615E0954CDFC8D" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactions_47CA9EF155F52CF87A615E0954CDFC8D" xlink:to="lab_us-gaap_FutureMinimumSubleaseRentalsSaleLeasebackTransactions_47CA9EF155F52CF87A615E0954CDFC8D" xlink:type="arc" />
    <link:label id="lab_biib_NetMinimumLeasePaymentsWithInOneYear_C1BFD5F03CF85E598BA75E0954CD98A4_totalLabel_en-US" xlink:label="lab_biib_NetMinimumLeasePaymentsWithInOneYear_C1BFD5F03CF85E598BA75E0954CD98A4" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net minimum lease payments, 2013</link:label>
    <link:label id="lab_biib_NetMinimumLeasePaymentsWithInOneYear_C1BFD5F03CF85E598BA75E0954CD98A4_label_en-US" xlink:label="lab_biib_NetMinimumLeasePaymentsWithInOneYear_C1BFD5F03CF85E598BA75E0954CD98A4" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Minimum Lease Payments With In One Year</link:label>
    <link:label id="lab_biib_NetMinimumLeasePaymentsWithInOneYear_C1BFD5F03CF85E598BA75E0954CD98A4_documentation_en-US" xlink:label="lab_biib_NetMinimumLeasePaymentsWithInOneYear_C1BFD5F03CF85E598BA75E0954CD98A4" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Net minimum lease payments with in one year.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_NetMinimumLeasePaymentsWithInOneYear" xlink:label="loc_biib_NetMinimumLeasePaymentsWithInOneYear_C1BFD5F03CF85E598BA75E0954CD98A4" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_biib_NetMinimumLeasePaymentsWithInOneYear_C1BFD5F03CF85E598BA75E0954CD98A4" xlink:to="lab_biib_NetMinimumLeasePaymentsWithInOneYear_C1BFD5F03CF85E598BA75E0954CD98A4" xlink:type="arc" />
    <link:label id="lab_biib_NetMinimumLeasePaymentsWithInTwoYear_368C1F646CB6DC7A95185E0954CDFD7D_totalLabel_en-US" xlink:label="lab_biib_NetMinimumLeasePaymentsWithInTwoYear_368C1F646CB6DC7A95185E0954CDFD7D" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net minimum lease payments, 2014</link:label>
    <link:label id="lab_biib_NetMinimumLeasePaymentsWithInTwoYear_368C1F646CB6DC7A95185E0954CDFD7D_label_en-US" xlink:label="lab_biib_NetMinimumLeasePaymentsWithInTwoYear_368C1F646CB6DC7A95185E0954CDFD7D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Minimum Lease Payments With In Two Year</link:label>
    <link:label id="lab_biib_NetMinimumLeasePaymentsWithInTwoYear_368C1F646CB6DC7A95185E0954CDFD7D_documentation_en-US" xlink:label="lab_biib_NetMinimumLeasePaymentsWithInTwoYear_368C1F646CB6DC7A95185E0954CDFD7D" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Net minimum lease payments with in two year.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_NetMinimumLeasePaymentsWithInTwoYear" xlink:label="loc_biib_NetMinimumLeasePaymentsWithInTwoYear_368C1F646CB6DC7A95185E0954CDFD7D" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_biib_NetMinimumLeasePaymentsWithInTwoYear_368C1F646CB6DC7A95185E0954CDFD7D" xlink:to="lab_biib_NetMinimumLeasePaymentsWithInTwoYear_368C1F646CB6DC7A95185E0954CDFD7D" xlink:type="arc" />
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    <link:label id="lab_biib_FairValueOfAssetsAndLiabilitiesAcquiredAndAssignedToNoncontrollingInterest_DA57DF83D670A78C5F14962688F5BC02_negatedLabel_en-US" xlink:label="lab_biib_FairValueOfAssetsAndLiabilitiesAcquiredAndAssignedToNoncontrollingInterest_DA57DF83D670A78C5F14962688F5BC02" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Fair value of assets and liabilities acquired and assigned to noncontrolling interests (Note 20)</link:label>
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    <link:label id="lab_biib_FairValueOfAssetsAndLiabilitiesAcquiredAndAssignedToNoncontrollingInterest_DA57DF83D670A78C5F14962688F5BC02_documentation_en-US" xlink:label="lab_biib_FairValueOfAssetsAndLiabilitiesAcquiredAndAssignedToNoncontrollingInterest_DA57DF83D670A78C5F14962688F5BC02" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Fair value of assets and liabilities acquired and assigned to noncontrolling interest.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_FairValueOfAssetsAndLiabilitiesAcquiredAndAssignedToNoncontrollingInterest" xlink:label="loc_biib_FairValueOfAssetsAndLiabilitiesAcquiredAndAssignedToNoncontrollingInterest_DA57DF83D670A78C5F14962688F5BC02" xlink:type="locator" />
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    <link:label id="lab_biib_NoncontrollingInterestIncreaseTerminationOfRelationshipWithLessThanMajorityOwnedSubsidiary_6E7597AADC0087EF8517962688F57FB8_documentation_en-US" xlink:label="lab_biib_NoncontrollingInterestIncreaseTerminationOfRelationshipWithLessThanMajorityOwnedSubsidiary_6E7597AADC0087EF8517962688F57FB8" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Noncontrolling Interest Increase Termination Of Relationship With Less Than Majority Owned Subsidiary.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_NoncontrollingInterestIncreaseTerminationOfRelationshipWithLessThanMajorityOwnedSubsidiary" xlink:label="loc_biib_NoncontrollingInterestIncreaseTerminationOfRelationshipWithLessThanMajorityOwnedSubsidiary_6E7597AADC0087EF8517962688F57FB8" xlink:type="locator" />
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    <link:label id="lab_biib_RetirementOfCommonStock_E860A50E536B7EB4DFEE962688F50ED5_negatedLabel_en-US" xlink:label="lab_biib_RetirementOfCommonStock_E860A50E536B7EB4DFEE962688F50ED5" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Retirement of common stock pursuant to the 2009 and 2010 share repurchase plans</link:label>
    <link:label id="lab_biib_RetirementOfCommonStock_E860A50E536B7EB4DFEE962688F50ED5_label_en-US" xlink:label="lab_biib_RetirementOfCommonStock_E860A50E536B7EB4DFEE962688F50ED5" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Retirement Of Common Stock</link:label>
    <link:label id="lab_biib_RetirementOfCommonStock_E860A50E536B7EB4DFEE962688F50ED5_documentation_en-US" xlink:label="lab_biib_RetirementOfCommonStock_E860A50E536B7EB4DFEE962688F50ED5" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Retirement of common stock.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_RetirementOfCommonStock" xlink:label="loc_biib_RetirementOfCommonStock_E860A50E536B7EB4DFEE962688F50ED5" xlink:type="locator" />
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    <link:label id="lab_biib_RetirementOfCommonStockShares_55F64774D65A7C725635962688F54389_negatedLabel_en-US" xlink:label="lab_biib_RetirementOfCommonStockShares_55F64774D65A7C725635962688F54389" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Retirement of common stock pursuant to the 2009 and 2010 share repurchase plans, shares</link:label>
    <link:label id="lab_biib_RetirementOfCommonStockShares_55F64774D65A7C725635962688F54389_label_en-US" xlink:label="lab_biib_RetirementOfCommonStockShares_55F64774D65A7C725635962688F54389" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Retirement Of Common Stock Shares</link:label>
    <link:label id="lab_biib_RetirementOfCommonStockShares_55F64774D65A7C725635962688F54389_documentation_en-US" xlink:label="lab_biib_RetirementOfCommonStockShares_55F64774D65A7C725635962688F54389" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Retirement of common stock shares.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_RetirementOfCommonStockShares" xlink:label="loc_biib_RetirementOfCommonStockShares_55F64774D65A7C725635962688F54389" xlink:type="locator" />
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    <link:label id="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_9E9DCCB7CD4EAAD78F0A962688F65E23_periodEndLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_9E9DCCB7CD4EAAD78F0A962688F65E23" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Ending Balance</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_9E9DCCB7CD4EAAD78F0A962688F65E23" xlink:type="locator" />
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    <link:label id="lab_us-gaap_SharesIssued_BB29743E7B458AD3C2C1962688F6C16D_periodEndLabel_en-US" xlink:label="lab_us-gaap_SharesIssued_BB29743E7B458AD3C2C1962688F6C16D" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Ending Balance, shares</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SharesIssued" xlink:label="loc_us-gaap_SharesIssued_BB29743E7B458AD3C2C1962688F6C16D" xlink:type="locator" />
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    <link:label id="lab_us-gaap_AccountsNotesAndLoansReceivableLineItems_4A84152A113E6E9969335D86A9061DFD_verboseLabel_en-US" xlink:label="lab_us-gaap_AccountsNotesAndLoansReceivableLineItems_4A84152A113E6E9969335D86A9061DFD" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Accounts Receivable (Textual)</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_4A84152A113E6E9969335D86A9061DFD" xlink:type="locator" />
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    <link:label id="lab_biib_MinimumTermForAccountsReceivable_DF051C8E7225A453C6A35D86A9069A8E_verboseLabel_en-US" xlink:label="lab_biib_MinimumTermForAccountsReceivable_DF051C8E7225A453C6A35D86A9069A8E" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Minimum term for accounts receivable</link:label>
    <link:label id="lab_biib_MinimumTermForAccountsReceivable_DF051C8E7225A453C6A35D86A9069A8E_label_en-US" xlink:label="lab_biib_MinimumTermForAccountsReceivable_DF051C8E7225A453C6A35D86A9069A8E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Minimum Term For Accounts Receivable</link:label>
    <link:label id="lab_biib_MinimumTermForAccountsReceivable_DF051C8E7225A453C6A35D86A9069A8E_documentation_en-US" xlink:label="lab_biib_MinimumTermForAccountsReceivable_DF051C8E7225A453C6A35D86A9069A8E" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Minimum term for accounts receivable.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_MinimumTermForAccountsReceivable" xlink:label="loc_biib_MinimumTermForAccountsReceivable_DF051C8E7225A453C6A35D86A9069A8E" xlink:type="locator" />
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    <link:label id="lab_biib_MaximumTermForAccountsReceivable_D67E6B15790509E36BEF5D86A906BF8C_verboseLabel_en-US" xlink:label="lab_biib_MaximumTermForAccountsReceivable_D67E6B15790509E36BEF5D86A906BF8C" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Maximum term for accounts receivable</link:label>
    <link:label id="lab_biib_MaximumTermForAccountsReceivable_D67E6B15790509E36BEF5D86A906BF8C_label_en-US" xlink:label="lab_biib_MaximumTermForAccountsReceivable_D67E6B15790509E36BEF5D86A906BF8C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Maximum Term For Accounts Receivable</link:label>
    <link:label id="lab_biib_MaximumTermForAccountsReceivable_D67E6B15790509E36BEF5D86A906BF8C_documentation_en-US" xlink:label="lab_biib_MaximumTermForAccountsReceivable_D67E6B15790509E36BEF5D86A906BF8C" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Maximum term for accounts receivable.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_MaximumTermForAccountsReceivable" xlink:label="loc_biib_MaximumTermForAccountsReceivable_D67E6B15790509E36BEF5D86A906BF8C" xlink:type="locator" />
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    <link:label id="lab_biib_AccountsReceivableOutstandingForGreaterThanOneYear_1A16DF8BF254415BB8135D86A9066997_verboseLabel_en-US" xlink:label="lab_biib_AccountsReceivableOutstandingForGreaterThanOneYear_1A16DF8BF254415BB8135D86A9066997" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Accounts receivable outstanding for greater than one year</link:label>
    <link:label id="lab_biib_AccountsReceivableOutstandingForGreaterThanOneYear_1A16DF8BF254415BB8135D86A9066997_label_en-US" xlink:label="lab_biib_AccountsReceivableOutstandingForGreaterThanOneYear_1A16DF8BF254415BB8135D86A9066997" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounts Receivable Outstanding For Greater Than One Year</link:label>
    <link:label id="lab_biib_AccountsReceivableOutstandingForGreaterThanOneYear_1A16DF8BF254415BB8135D86A9066997_documentation_en-US" xlink:label="lab_biib_AccountsReceivableOutstandingForGreaterThanOneYear_1A16DF8BF254415BB8135D86A9066997" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Amounts due from customers, greater than one year outstanding for goods or services (including trade receivables) that have been delivered or sold in the normal course of business.</link:label>
    <link:loc xlink:href="biib-20121231.xsd#biib_AccountsReceivableOutstandingForGreaterThanOneYear" xlink:label="loc_biib_AccountsReceivableOutstandingForGreaterThanOneYear_1A16DF8BF254415BB8135D86A9066997" xlink:type="locator" />
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    <link:label id="lab_biib_DecreaseInAccountsReceivable_5AF95ABF210475A112FD5D86A9078EA5_terseLabel_en-US" xlink:label="lab_biib_DecreaseInAccountsReceivable_5AF95ABF210475A112FD5D86A9078EA5" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Decrease In accounts receivable in Spain</link:label>
    <link:label id="lab_biib_DecreaseInAccountsReceivable_5AF95ABF210475A112FD5D86A9078EA5_label_en-US" xlink:label="lab_biib_DecreaseInAccountsReceivable_5AF95ABF210475A112FD5D86A9078EA5" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Decrease In Accounts Receivable</link:label>
    <link:label id="lab_biib_DecreaseInAccountsReceivable_5AF95ABF210475A112FD5D86A9078EA5_documentation_en-US" xlink:label="lab_biib_DecreaseInAccountsReceivable_5AF95ABF210475A112FD5D86A9078EA5" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Decrease in accounts receivable.</link:label>
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    <link:label id="lab_us-gaap_AccountsReceivableNet_FB58B41FFB353E124ACB5D86A907E2F1_terseLabel_en-US" xlink:label="lab_us-gaap_AccountsReceivableNet_FB58B41FFB353E124ACB5D86A907E2F1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accounts receivable, net</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccountsReceivableNet" xlink:label="loc_us-gaap_AccountsReceivableNet_FB58B41FFB353E124ACB5D86A907E2F1" xlink:type="locator" />
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    <link:label id="lab_biib_DeferredRevenueOnSales_56FA80C16AEF0E087E685D86A907093D_terseLabel_en-US" xlink:label="lab_biib_DeferredRevenueOnSales_56FA80C16AEF0E087E685D86A907093D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Deferred revenue on sales of TYSABRI made in Italy</link:label>
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    <link:label id="lab_biib_DeferredRevenueOnSales_56FA80C16AEF0E087E685D86A907093D_documentation_en-US" xlink:label="lab_biib_DeferredRevenueOnSales_56FA80C16AEF0E087E685D86A907093D" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Deferred revenue on sales.</link:label>
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    <link:label id="lab_us-gaap_SellingGeneralAndAdministrativeExpense_DD699A1C1E5DB6E8B8EA96268911036B_verboseLabel_en-US" xlink:label="lab_us-gaap_SellingGeneralAndAdministrativeExpense_DD699A1C1E5DB6E8B8EA96268911036B" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Selling, general and administrative</link:label>
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    <link:label id="lab_biib_PercentageOfCoPromotionOperatingProfitsGreaterThanFirstFiftyMillionOptionThree_5C8039F88136FCC3D92B9AA06B4FDC6B_verboseLabel_en-US" xlink:label="lab_biib_PercentageOfCoPromotionOperatingProfitsGreaterThanFirstFiftyMillionOptionThree_5C8039F88136FCC3D92B9AA06B4FDC6B" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">After Second GA101 Threshold Date</link:label>
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    <link:label id="lab_biib_ReimbursementOfSellingAndDevelopmentExpenses_20BADA3FD2AC821E975C9AA06B508BDD_verboseLabel_en-US" xlink:label="lab_biib_ReimbursementOfSellingAndDevelopmentExpenses_20BADA3FD2AC821E975C9AA06B508BDD" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Reimbursement of our selling and development expenses in the U.S</link:label>
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    <link:label id="lab_us-gaap_LongTermDebtCurrentAbstract_DB2FD75C0DEFB996A86D162672A2C8C3_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtCurrentAbstract_DB2FD75C0DEFB996A86D162672A2C8C3" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Current portion:</link:label>
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    <link:label id="lab_us-gaap_LongTermDebtNoncurrentAbstract_6C08FE555059D12ADAED162672A2EEE8_label_en-US" xlink:label="lab_us-gaap_LongTermDebtNoncurrentAbstract_6C08FE555059D12ADAED162672A2EEE8" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-term Debt, Excluding Current Maturities [Abstract]</link:label>
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