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  <xsd:element abstract="true" id="regn_DistributionRelatedFeesMember" name="DistributionRelatedFeesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="regn_DocumentAndEntityInformationAbstract" name="DocumentAndEntityInformationAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="regn_EyleaNetProductSalesMember" name="EyleaNetProductSalesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="regn_FacilityLeaseObligationIncludingReimbursements" name="FacilityLeaseObligationIncludingReimbursements" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="regn_FacilityLeaseObligationsCurrent" name="FacilityLeaseObligationsCurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="regn_FacilityLeaseObligationsNoncurrent" name="FacilityLeaseObligationsNoncurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="regn_Firstpaymentmadeormaybemadeuponreachingminimumsalestarget" name="Firstpaymentmadeormaybemadeuponreachingminimumsalestarget" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="regn_GlobalMember" name="GlobalMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="regn_GrosssalesrevenueMember" name="GrosssalesrevenueMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="regn_IncrementalCommonSharesAttributableToNonvestedRestrictedShares" name="IncrementalCommonSharesAttributableToNonvestedRestrictedShares" nillable="true" substitutionGroup="xbrli:item" type="xbrli:sharesItemType" xbrli:periodType="duration" />
  <xsd:element id="regn_InitialTermOfLease" name="InitialTermOfLease" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="regn_LeaseExtensionTerms" name="LeaseExtensionTerms" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="regn_LicenseAgreementWithGenentechMember" name="LicenseAgreementWithGenentechMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="regn_LicenseAgreementWithGenentechZaltrapMember" name="LicenseAgreementWithGenentechZaltrapMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="regn_LossContingenciesByGeographicAreaAxis" name="LossContingenciesByGeographicAreaAxis" nillable="true" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="regn_LossContingenciesByGeographicAreaDomain" name="LossContingenciesByGeographicAreaDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="regn_MaximumAmountOfSalesMilestonePaymentsIfTotalSalesAchieveSpecificLevels" name="MaximumAmountOfSalesMilestonePaymentsIfTotalSalesAchieveSpecificLevels" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="regn_MaximumamountofsubstantivemilestonepaymentsthatmaybereceivedinmajormarketcountriesoutsidetheUS" name="MaximumamountofsubstantivemilestonepaymentsthatmaybereceivedinmajormarketcountriesoutsidetheUS" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:periodType="duration" />
  <xsd:element id="regn_Maximumlevelsofannualsalesforwhichsalesmilestonepaymentsmaybereceived" name="Maximumlevelsofannualsalesforwhichsalesmilestonepaymentsmaybereceived" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="regn_MilestonepaymentachievementAxis" name="MilestonepaymentachievementAxis" nillable="true" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="regn_NetProfitFromCommercializationOfProductsUnderCollaborationAgreement" name="NetProfitFromCommercializationOfProductsUnderCollaborationAgreement" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:periodType="duration" />
  <xsd:element id="regn_NetProfitLossFromCommercializationOfProductsUnderCollaborationAgreement" name="NetProfitLossFromCommercializationOfProductsUnderCollaborationAgreement" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="regn_NewLaboratoryAndOfficeFacilitiesMember" name="NewLaboratoryAndOfficeFacilitiesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="regn_NonCashInterestExpense" name="NonCashInterestExpense" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="regn_NumberOfMarketableSecuritiesHeld" name="NumberOfMarketableSecuritiesHeld" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element id="regn_NumberOfNewBuildingsToBeConstructed" name="NumberOfNewBuildingsToBeConstructed" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="regn_NumberOfRenewalOptions" name="NumberOfRenewalOptions" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <xsd:element id="regn_Numberoffamiliesofnovelantibodies" name="Numberoffamiliesofnovelantibodies" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="regn_Numberofsalesmilestones" name="Numberofsalesmilestones" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="regn_Numberofupfrontpayments" name="Numberofupfrontpayments" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="regn_OtherCollaborationRevenue" name="OtherCollaborationRevenue" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="regn_OtherSalesRelatedDeductionsMember" name="OtherSalesRelatedDeductionsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="regn_PdgfMember" name="PdgfMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="regn_Periodforachievingsalestargetformilestonepaymentrollingbasis" name="Periodforachievingsalestargetformilestonepaymentrollingbasis" nillable="true" substitutionGroup="xbrli:item" type="us-types:durationStringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="regn_RebatesAndChargebacksMember" name="RebatesAndChargebacksMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="regn_ReceiptofmarketingapprovalDomain" name="ReceiptofmarketingapprovalDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="regn_ReceiptofmarketingapprovalMember" name="ReceiptofmarketingapprovalMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="regn_ReimbursementOfCommercialExpenses" name="ReimbursementOfCommercialExpenses" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="regn_ResearchCollaborationAndLicensingAgreementsAxis" name="ResearchCollaborationAndLicensingAgreementsAxis" nillable="true" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="regn_ResearchCollaborationAndLicensingAgreementsDomain" name="ResearchCollaborationAndLicensingAgreementsDomain" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="regn_RestrictedMember" name="RestrictedMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="regn_RevenueAndConcentrationRiskDisclosureTextBlock" name="RevenueAndConcentrationRiskDisclosureTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="regn_RevenueDisclosureTable" name="RevenueDisclosureTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="regn_Royaltypaymentpercentageofcumulativesale1sttier" name="Royaltypaymentpercentageofcumulativesale1sttier" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="regn_Royaltypaymentpercentageofsales2ndtier" name="Royaltypaymentpercentageofsales2ndtier" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="regn_Salesachievement300millionMember" name="Salesachievement300millionMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="regn_SalesachievementMember" name="SalesachievementMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="regn_Salesrangemaximum1sttier" name="Salesrangemaximum1sttier" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:periodType="duration" />
  <xsd:element id="regn_Salesrangeminimum1sttier" name="Salesrangeminimum1sttier" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:periodType="duration" />
  <xsd:element id="regn_ScheduleOfSalesRelatedDeductionsActivityTableTextBlock" name="ScheduleOfSalesRelatedDeductionsActivityTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="regn_StartingSpecifiedLevelsOfAnnualSalesAtWhichSalesMilestonePaymentsMayBeReceived" name="StartingSpecifiedLevelsOfAnnualSalesAtWhichSalesMilestonePaymentsMayBeReceived" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="regn_Startingspecifiedlevelsofannualsalesatwhichsalesmilestonepaymentsmaybereceived1sttier" name="Startingspecifiedlevelsofannualsalesatwhichsalesmilestonepaymentsmaybereceived1sttier" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="regn_SubstantiveMilestonePayments" name="SubstantiveMilestonePayments" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="regn_UnrestrictedMember" name="UnrestrictedMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="regn_VelocigeneAgreementMember" name="VelocigeneAgreementMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="regn_ZaltrapMember" name="ZaltrapMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
</xsd:schema>
