<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019c2a01-c194-798d-9d04-f2aea2ae7e83,g:e5eab2f8-f177-4ecc-b854-6c1a6c0648c6-->
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:regn="http://www.regeneron.com/20260331" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:dtr-types="http://www.xbrl.org/dtr/type/2024-01-31" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" attributeFormDefault="unqualified" elementFormDefault="qualified" targetNamespace="http://www.regeneron.com/20260331">
  <xs:import namespace="http://fasb.org/srt/2025" schemaLocation="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd"/>
  <xs:import namespace="http://fasb.org/us-gaap/2025" schemaLocation="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd"/>
  <xs:import namespace="http://www.xbrl.org/2003/instance" schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd"/>
  <xs:import namespace="http://www.xbrl.org/2003/linkbase" schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd"/>
  <xs:import namespace="http://www.xbrl.org/dtr/type/2024-01-31" schemaLocation="https://www.xbrl.org/dtr/type/2024-01-31/types.xsd"/>
  <xs:import namespace="http://xbrl.org/2005/xbrldt" schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/country/2025" schemaLocation="https://xbrl.sec.gov/country/2025/country-2025.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/dei/2025" schemaLocation="https://xbrl.sec.gov/dei/2025/dei-2025.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/ecd/2025" schemaLocation="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd"/>
  <xs:annotation>
    <xs:appinfo>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="regn-20260331_pre.xml" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="regn-20260331_def.xml" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="regn-20260331_lab.xml" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="regn-20260331_cal.xml" xlink:role="http://www.xbrl.org/2003/role/calculationLinkbaseRef" xlink:type="simple"/>
      <link:roleType id="Cover" roleURI="http://www.regeneron.com/role/Cover">
        <link:definition>0000001 - Document - Cover</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CONDENSEDCONSOLIDATEDBALANCESHEETSUnaudited" roleURI="http://www.regeneron.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETSUnaudited">
        <link:definition>9952151 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CONDENSEDCONSOLIDATEDBALANCESHEETSUnauditedParenthetical" roleURI="http://www.regeneron.com/role/CONDENSEDCONSOLIDATEDBALANCESHEETSUnauditedParenthetical">
        <link:definition>9952152 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONSANDCOMPREHENSIVEINCOMEUnaudited" roleURI="http://www.regeneron.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFOPERATIONSANDCOMPREHENSIVEINCOMEUnaudited">
        <link:definition>9952153 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (Unaudited)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CONDENSEDCONSOLIDATEDSTATEMENTSOFSTOCKHOLDERSEQUITYUnaudited" roleURI="http://www.regeneron.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFSTOCKHOLDERSEQUITYUnaudited">
        <link:definition>9952154 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CONDENSEDCONSOLIDATEDSTATEMENTSOFCASHFLOWSUnaudited" roleURI="http://www.regeneron.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCASHFLOWSUnaudited">
        <link:definition>9952155 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="InterimFinancialStatements" roleURI="http://www.regeneron.com/role/InterimFinancialStatements">
        <link:definition>9952156 - Disclosure - Interim Financial Statements</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ProductSales" roleURI="http://www.regeneron.com/role/ProductSales">
        <link:definition>9952157 - Disclosure - Product Sales</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CollaborationLicenseandOtherAgreements" roleURI="http://www.regeneron.com/role/CollaborationLicenseandOtherAgreements">
        <link:definition>9952158 - Disclosure - Collaboration, License, and Other Agreements</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="NetIncomePerShare" roleURI="http://www.regeneron.com/role/NetIncomePerShare">
        <link:definition>9952159 - Disclosure - Net Income Per Share</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="MarketableSecurities" roleURI="http://www.regeneron.com/role/MarketableSecurities">
        <link:definition>9952160 - Disclosure - Marketable Securities</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValueMeasurements" roleURI="http://www.regeneron.com/role/FairValueMeasurements">
        <link:definition>9952161 - Disclosure - Fair Value Measurements</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Inventories" roleURI="http://www.regeneron.com/role/Inventories">
        <link:definition>9952162 - Disclosure - Inventories</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="IncomeTaxes" roleURI="http://www.regeneron.com/role/IncomeTaxes">
        <link:definition>9952163 - Disclosure - Income Taxes</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockholdersEquity" roleURI="http://www.regeneron.com/role/StockholdersEquity">
        <link:definition>9952164 - Disclosure - Stockholders' Equity</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StatementofCashFlows" roleURI="http://www.regeneron.com/role/StatementofCashFlows">
        <link:definition>9952165 - Disclosure - Statement of Cash Flows</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentInformation" roleURI="http://www.regeneron.com/role/SegmentInformation">
        <link:definition>9952166 - Disclosure - Segment Information</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LegalMatters" roleURI="http://www.regeneron.com/role/LegalMatters">
        <link:definition>9952167 - Disclosure - Legal Matters</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="InterimFinancialStatementsPolicies" roleURI="http://www.regeneron.com/role/InterimFinancialStatementsPolicies">
        <link:definition>9955511 - Disclosure - Interim Financial Statements (Policies)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="InterimFinancialStatementsTables" roleURI="http://www.regeneron.com/role/InterimFinancialStatementsTables">
        <link:definition>9955512 - Disclosure - Interim Financial Statements (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ProductSalesTables" roleURI="http://www.regeneron.com/role/ProductSalesTables">
        <link:definition>9955513 - Disclosure - Product Sales (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CollaborationLicenseandOtherAgreementsTables" roleURI="http://www.regeneron.com/role/CollaborationLicenseandOtherAgreementsTables">
        <link:definition>9955514 - Disclosure - Collaboration, License, and Other Agreements (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="NetIncomePerShareTables" roleURI="http://www.regeneron.com/role/NetIncomePerShareTables">
        <link:definition>9955515 - Disclosure - Net Income Per Share (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="MarketableSecuritiesTables" roleURI="http://www.regeneron.com/role/MarketableSecuritiesTables">
        <link:definition>9955516 - Disclosure - Marketable Securities (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValueMeasurementsTables" roleURI="http://www.regeneron.com/role/FairValueMeasurementsTables">
        <link:definition>9955517 - Disclosure - Fair Value Measurements (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="InventoriesTables" roleURI="http://www.regeneron.com/role/InventoriesTables">
        <link:definition>9955518 - Disclosure - Inventories (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockholdersEquityTables" roleURI="http://www.regeneron.com/role/StockholdersEquityTables">
        <link:definition>9955519 - Disclosure - Stockholders' Equity (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StatementofCashFlowsTables" roleURI="http://www.regeneron.com/role/StatementofCashFlowsTables">
        <link:definition>9955520 - Disclosure - Statement of Cash Flows (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentInformationTables" roleURI="http://www.regeneron.com/role/SegmentInformationTables">
        <link:definition>9955521 - Disclosure - Segment Information (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ProductSalesScheduleofNetProductSalesDetails" roleURI="http://www.regeneron.com/role/ProductSalesScheduleofNetProductSalesDetails">
        <link:definition>9955522 - Disclosure - Product Sales - Schedule of Net Product Sales (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ProductSalesNarrativeDetails" roleURI="http://www.regeneron.com/role/ProductSalesNarrativeDetails">
        <link:definition>9955523 - Disclosure - Product Sales - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="ProductSalesScheduleofConcentrationofRiskbyRiskFactorDetails" roleURI="http://www.regeneron.com/role/ProductSalesScheduleofConcentrationofRiskbyRiskFactorDetails">
        <link:definition>9955524 - Disclosure - Product Sales - Schedule of Concentration of Risk, by Risk Factor (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CollaborationLicenseandOtherAgreementsSanofiAntibodyNarrativeDetails" roleURI="http://www.regeneron.com/role/CollaborationLicenseandOtherAgreementsSanofiAntibodyNarrativeDetails">
        <link:definition>9955525 - Disclosure - Collaboration, License, and Other Agreements - Sanofi, Antibody Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CollaborationLicenseandOtherAgreementsAmountsRecognizedInStatementofOperationswithSanofiDetails" roleURI="http://www.regeneron.com/role/CollaborationLicenseandOtherAgreementsAmountsRecognizedInStatementofOperationswithSanofiDetails">
        <link:definition>9955526 - Disclosure - Collaboration, License, and Other Agreements - Amounts Recognized In Statement of Operations with Sanofi (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CollaborationLicenseandOtherAgreementsScheduleofContractBalancesAntibodyCollaborationDetails" roleURI="http://www.regeneron.com/role/CollaborationLicenseandOtherAgreementsScheduleofContractBalancesAntibodyCollaborationDetails">
        <link:definition>9955527 - Disclosure - Collaboration, License, and Other Agreements - Schedule of Contract Balances, Antibody Collaboration (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CollaborationLicenseandOtherAgreementsAmountsRecognizedinStatementofOperationswithBayerDetails" roleURI="http://www.regeneron.com/role/CollaborationLicenseandOtherAgreementsAmountsRecognizedinStatementofOperationswithBayerDetails">
        <link:definition>9955528 - Disclosure - Collaboration, License, and Other Agreements - Amounts Recognized in Statement of Operations with Bayer (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CollaborationLicenseandOtherAgreementsScheduleofContractBalancesBayerCollaborationDetails" roleURI="http://www.regeneron.com/role/CollaborationLicenseandOtherAgreementsScheduleofContractBalancesBayerCollaborationDetails">
        <link:definition>9955529 - Disclosure - Collaboration, License, and Other Agreements - Schedule of Contract Balances, Bayer Collaboration (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="NetIncomePerShareScheduleofBasicandDilutedNetIncomePerShareDetails" roleURI="http://www.regeneron.com/role/NetIncomePerShareScheduleofBasicandDilutedNetIncomePerShareDetails">
        <link:definition>9955530 - Disclosure - Net Income Per Share - Schedule of Basic and Diluted Net Income Per Share (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="NetIncomePerShareScheduleofAntidilutiveSecuritiesExcludedFromComputationDetails" roleURI="http://www.regeneron.com/role/NetIncomePerShareScheduleofAntidilutiveSecuritiesExcludedFromComputationDetails">
        <link:definition>9955531 - Disclosure - Net Income Per Share - Schedule of Antidilutive Securities Excluded From Computation (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="MarketableSecuritiesScheduleofInvestmentsinAvailableForSaleDebtSecuritiesDetails" roleURI="http://www.regeneron.com/role/MarketableSecuritiesScheduleofInvestmentsinAvailableForSaleDebtSecuritiesDetails">
        <link:definition>9955532 - Disclosure - Marketable Securities - Schedule of Investments in Available For Sale Debt Securities (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="MarketableSecuritiesScheduleofDebtSecuritiesBasedonContractualMaturityDatesDetails" roleURI="http://www.regeneron.com/role/MarketableSecuritiesScheduleofDebtSecuritiesBasedonContractualMaturityDatesDetails">
        <link:definition>9955533 - Disclosure - Marketable Securities - Schedule of Debt Securities Based on Contractual Maturity Dates (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValueMeasurementsScheduleofAssetsMeasuredatFairValueonaRecurringBasisDetails" roleURI="http://www.regeneron.com/role/FairValueMeasurementsScheduleofAssetsMeasuredatFairValueonaRecurringBasisDetails">
        <link:definition>9955534 - Disclosure - Fair Value Measurements - Schedule of Assets Measured at Fair Value on a Recurring Basis (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FairValueMeasurementsNarrativeDetails" roleURI="http://www.regeneron.com/role/FairValueMeasurementsNarrativeDetails">
        <link:definition>9955535 - Disclosure - Fair Value Measurements - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="InventoriesDetails" roleURI="http://www.regeneron.com/role/InventoriesDetails">
        <link:definition>9955536 - Disclosure - Inventories (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="IncomeTaxesDetails" roleURI="http://www.regeneron.com/role/IncomeTaxesDetails">
        <link:definition>9955537 - Disclosure - Income Taxes (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockholdersEquityNarrativeDetails" roleURI="http://www.regeneron.com/role/StockholdersEquityNarrativeDetails">
        <link:definition>9955538 - Disclosure - Stockholders' Equity - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockholdersEquityScheduleofShareRepurchasesDetails" roleURI="http://www.regeneron.com/role/StockholdersEquityScheduleofShareRepurchasesDetails">
        <link:definition>9955539 - Disclosure - Stockholders' Equity - Schedule of Share Repurchases (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StatementofCashFlowsScheduleofReconciliationofCashCashEquivalentsandRestrictedCashDetails" roleURI="http://www.regeneron.com/role/StatementofCashFlowsScheduleofReconciliationofCashCashEquivalentsandRestrictedCashDetails">
        <link:definition>9955540 - Disclosure - Statement of Cash Flows - Schedule of Reconciliation of Cash, Cash Equivalents, and Restricted Cash (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StatementofCashFlowsSummaryofNoncashInvestingandFinancingActivitiesDetails" roleURI="http://www.regeneron.com/role/StatementofCashFlowsSummaryofNoncashInvestingandFinancingActivitiesDetails">
        <link:definition>9955541 - Disclosure - Statement of Cash Flows - Summary of Non-cash Investing and Financing Activities (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentInformationNarrativeDetails" roleURI="http://www.regeneron.com/role/SegmentInformationNarrativeDetails">
        <link:definition>9955542 - Disclosure - Segment Information - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentInformationScheduleofSignificantExpensesDetails" roleURI="http://www.regeneron.com/role/SegmentInformationScheduleofSignificantExpensesDetails">
        <link:definition>9955543 - Disclosure - Segment Information - Schedule of Significant Expenses (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="LegalMattersDetails" roleURI="http://www.regeneron.com/role/LegalMattersDetails">
        <link:definition>9955544 - Disclosure - Legal Matters (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
    </xs:appinfo>
  </xs:annotation>
  <xs:element id="regn_CollaborationRevenueMember" abstract="true" name="CollaborationRevenueMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_CollaborationandContractManufacturingMember" abstract="true" name="CollaborationandContractManufacturingMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_AcquiredInProcessResearchAndDevelopment" abstract="false" name="AcquiredInProcessResearchAndDevelopment" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="regn_StockIssuedDistributedDuringPeriodValueEmployeeBenefitPlan" abstract="false" name="StockIssuedDistributedDuringPeriodValueEmployeeBenefitPlan" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="regn_MarketableAndOtherSecuritiesGainLoss" abstract="false" name="MarketableAndOtherSecuritiesGainLoss" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="regn_PaymentsToAcquireIntangibleAssets1" abstract="false" name="PaymentsToAcquireIntangibleAssets1" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="regn_EYLEAHDAndEYLEAMember" abstract="true" name="EYLEAHDAndEYLEAMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_EYLEAHDMember" abstract="true" name="EYLEAHDMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_EyleaNetProductSalesMember" abstract="true" name="EyleaNetProductSalesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_LIBTAYONetProductSalesMember" abstract="true" name="LIBTAYONetProductSalesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_PraluentNetProductSalesMember" abstract="true" name="PraluentNetProductSalesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_EvkeezaMember" abstract="true" name="EvkeezaMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_OtherProductsMember" abstract="true" name="OtherProductsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_LynozyficMember" abstract="true" name="LynozyficMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_GrossProductRevenueMember" abstract="true" name="GrossProductRevenueMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_CustomerAMember" abstract="true" name="CustomerAMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_CustomerBMember" abstract="true" name="CustomerBMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_SanofiCollaborationAgreementAntibodyMember" abstract="true" name="SanofiCollaborationAgreementAntibodyMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_PercentageOfTrialCostsRequiredToBeFundedByCollaboratingParty" abstract="false" name="PercentageOfTrialCostsRequiredToBeFundedByCollaboratingParty" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="regn_PercentageOfQuarterlyProfitsRequiredToBePaidForReimbursementOfDevelopmentCosts" abstract="false" name="PercentageOfQuarterlyProfitsRequiredToBePaidForReimbursementOfDevelopmentCosts" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="regn_ContingentReimbursementObligation" abstract="false" name="ContingentReimbursementObligation" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="regn_StartingShareOfProfitsOutsideUnitedStatesBasedOnSalesForCollaboratingParty" abstract="false" name="StartingShareOfProfitsOutsideUnitedStatesBasedOnSalesForCollaboratingParty" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="regn_StartingShareOfProfitsOutsideUnitedStatesBasedOnSalesForCompany" abstract="false" name="StartingShareOfProfitsOutsideUnitedStatesBasedOnSalesForCompany" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="regn_EndingShareOfProfitsOutsideUnitedStatesBasedOnSalesForCollaboratingParty" abstract="false" name="EndingShareOfProfitsOutsideUnitedStatesBasedOnSalesForCollaboratingParty" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="regn_EndingShareOfProfitsOutsideUnitedStatesBasedOnSalesForCompany" abstract="false" name="EndingShareOfProfitsOutsideUnitedStatesBasedOnSalesForCompany" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="regn_ShareOfProfitLossesMember" abstract="true" name="ShareOfProfitLossesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_ReimbursementForManufacturingOfCommercialSuppliesMember" abstract="true" name="ReimbursementForManufacturingOfCommercialSuppliesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_ReimbursementOfResearchAndDevelopmentExpensesNetOfObligationForShareOfRDExpensesMember" abstract="true" name="ReimbursementOfResearchAndDevelopmentExpensesNetOfObligationForShareOfRDExpensesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_ReimbursementOfCommercializationRelatedExpensesMember" abstract="true" name="ReimbursementOfCommercializationRelatedExpensesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_BayerCollaborationAgreementMember" abstract="true" name="BayerCollaborationAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_RegeneronsObligationOfResearchAndDevelopmentExpensesNetOfReimbursementOfResearchAndDevelopmentExpensesMember" abstract="true" name="RegeneronsObligationOfResearchAndDevelopmentExpensesNetOfReimbursementOfResearchAndDevelopmentExpensesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_DebtSecuritiesAvailableForSaleFairValueMaturityAllocatedAndSingleMaturityDateAfterYear5" abstract="false" name="DebtSecuritiesAvailableForSaleFairValueMaturityAllocatedAndSingleMaturityDateAfterYear5" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="regn_ClassificationOfInvestmentAxis" abstract="true" name="ClassificationOfInvestmentAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="regn_ClassificationOfInvestmentDomain" abstract="true" name="ClassificationOfInvestmentDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_RestrictedMember" abstract="true" name="RestrictedMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_ShareRepurchaseProgramFebruary2025Member" abstract="true" name="ShareRepurchaseProgramFebruary2025Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_ShareRepurchaseProgramApril2026Member" abstract="true" name="ShareRepurchaseProgramApril2026Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_AcquisitionsContingentConsiderationAccruedButNotYetPaid" abstract="false" name="AcquisitionsContingentConsiderationAccruedButNotYetPaid" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="regn_ReportableSegmentMember" abstract="true" name="ReportableSegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_ResearchAndDevelopmentExpenseTypeAxis" abstract="true" name="ResearchAndDevelopmentExpenseTypeAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="regn_ResearchAndDevelopmentExpenseTypeDomain" abstract="true" name="ResearchAndDevelopmentExpenseTypeDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_DirectExpenseMember" abstract="true" name="DirectExpenseMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_IndirectExpenseMember" abstract="true" name="IndirectExpenseMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_PayrollAndBenefitsMember" abstract="true" name="PayrollAndBenefitsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_LabSuppliesAndOtherResearchAndDevelopmentCostsMember" abstract="true" name="LabSuppliesAndOtherResearchAndDevelopmentCostsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_OccupancyAndOtherOperatingCostsMember" abstract="true" name="OccupancyAndOtherOperatingCostsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_ClinicalAndManufacturingCostsMember" abstract="true" name="ClinicalAndManufacturingCostsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_ResearchAndDevelopmentExpenseReimbursements" abstract="false" name="ResearchAndDevelopmentExpenseReimbursements" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="regn_LitigationDamagesTypeAxis" abstract="true" name="LitigationDamagesTypeAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="regn_LitigationDamagesTypeDomain" abstract="true" name="LitigationDamagesTypeDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_CompensatoryDamagesMember" abstract="true" name="CompensatoryDamagesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_PunitiveDamagesMember" abstract="true" name="PunitiveDamagesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_RegeneronVs.AmgenMember" abstract="true" name="RegeneronVs.AmgenMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_NumberOfCountsSubmitted" abstract="false" name="NumberOfCountsSubmitted" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="regn_NumberOfCountsRuledInFavorOfPlaintiff" abstract="false" name="NumberOfCountsRuledInFavorOfPlaintiff" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="regn_MichaelS.BrownM.D.Member" abstract="true" name="MichaelS.BrownM.D.Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_JosephL.GoldsteinM.D.Member" abstract="true" name="JosephL.GoldsteinM.D.Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_KathrynGuariniPh.D.Member" abstract="true" name="KathrynGuariniPh.D.Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="regn_MarionMcCourtMember" abstract="true" name="MarionMcCourtMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
</xs:schema>
