content: <?xml version="1.0" encoding="UTF-8"?><edgarSubmission xmlns="http://www.sec.gov/edgar/ownership" xmlns:com="http://www.sec.gov/edgar/common">
    <!-- Generated by Workiva -->
    <headerData>
      <submissionType>144</submissionType>
      <filerInfo>
        <filer>
          <filerCredentials>
            <cik>0001756941</cik>
            <ccc>XXXXXXXX</ccc>
          </filerCredentials>
        </filer>
        <liveTestFlag>LIVE</liveTestFlag>
  
  
  
      </filerInfo>
    </headerData>
    <formData>
      <issuerInfo>
        <issuerCik>0001597264</issuerCik>
        <issuerName>Blueprint  Medicines Corporation</issuerName>
        <secFileNumber>001-37359</secFileNumber>
        <issuerAddress>
          <com:street1>45 Sidney Street</com:street1>
          <com:city>Cambridge</com:city>
          <com:stateOrCountry>MA</com:stateOrCountry>
          <com:zipCode>02139</com:zipCode>
        </issuerAddress>
        <issuerContactPhone>617-374-7580</issuerContactPhone>
        <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>Christina Rossi and Gregory Papp</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
        <relationshipsToIssuer>
          <relationshipToIssuer>Affiliate</relationshipToIssuer>
        </relationshipsToIssuer>
      </issuerInfo>
      <securitiesInformation>
        <securitiesClassTitle>Common Stock</securitiesClassTitle>
        <brokerOrMarketmakerDetails>
          <name>J.P. Morgan Securities LLC</name>
          <address>
            <com:street1>390 Madison Avenue</com:street1>
            <com:street2>6th Floor</com:street2>
            <com:city>New York</com:city>
            <com:stateOrCountry>NY</com:stateOrCountry>
            <com:zipCode>10017</com:zipCode>
          </address>
        </brokerOrMarketmakerDetails>
        <noOfUnitsSold>9096</noOfUnitsSold>
        <aggregateMarketValue>860754.48</aggregateMarketValue>
        <noOfUnitsOutstanding>63525838</noOfUnitsOutstanding>
        <approxSaleDate>11/27/2024</approxSaleDate>
        <securitiesExchangeName>NASDAQ</securitiesExchangeName>
      </securitiesInformation>
      <securitiesToBeSold>
        <securitiesClassTitle>Common Stock</securitiesClassTitle>
        <acquiredDate>11/01/2019</acquiredDate>
        <natureOfAcquisitionTransaction>Restricted Stock Grant</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>9096</amountOfSecuritiesAcquired>
        <paymentDate>11/01/2019</paymentDate>
        <natureOfPayment>Cash</natureOfPayment>
      </securitiesToBeSold>
      <nothingToReportFlagOnSecuritiesSoldInPast3Months>Y</nothingToReportFlagOnSecuritiesSoldInPast3Months>
      <remarks>The shares represented on this filing were acquired during 11/01/19 - 3/01/22.</remarks>
      <noticeSignature>
        <noticeDate>11/27/2024</noticeDate>
        <planAdoptionDates>
          <planAdoptionDate>08/27/2024</planAdoptionDate>
        </planAdoptionDates>
        <signature>/s/ J.P. Morgan Securities LLC as agent and attorney-in-fact for Christina Rossi</signature>
      </noticeSignature>
    </formData>
  </edgarSubmission>
metadata_documents: [{"type": "144", "sequence": "1", "filename": "primary_doc.xml", "secsgml_size_bytes": 3100}]
text: 144
  0001756941
  XXXXXXXX
  LIVE
  0001597264
  Blueprint  Medicines Corporation
  001-37359
  45 Sidney Street
  Cambridge
  MA
  02139
  617-374-7580
  Christina Rossi and Gregory Papp
  Affiliate
  Common Stock
  J.P. Morgan Securities LLC
  390 Madison Avenue
  6th Floor
  New York
  NY
  10017
  9096
  860754.48
  63525838
  11/27/2024
  NASDAQ
  Common Stock
  11/01/2019
  Restricted Stock Grant
  Issuer
  N
  9096
  11/01/2019
  Cash
  Y
  The shares represented on this filing were acquired during 11/01/19 - 3/01/22.
  11/27/2024
  08/27/2024
  /s/ J.P. Morgan Securities LLC as agent and attorney-in-fact for Christina Rossi