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            <filer>
                <filerCredentials>
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                    <ccc>XXXXXXXX</ccc>
                </filerCredentials>
            </filer>
            <liveTestFlag>LIVE</liveTestFlag>



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        <issuerInfo>
            <issuerCik>0001649904</issuerCik>
            <issuerName>RHYTHM PHARMACEUTICALS, INC.</issuerName>
            <secFileNumber>001-38223</secFileNumber>
            <issuerAddress>
                <ns2:street1>222 Berkeley Street, 12th Floor</ns2:street1>
                <ns2:city>BOSTON</ns2:city>
                <ns2:stateOrCountry>MA</ns2:stateOrCountry>
                <ns2:zipCode>02116</ns2:zipCode>
            </issuerAddress>
            <issuerContactPhone>8572644280</issuerContactPhone>
            <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>HUNTER SMITH</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
            <relationshipsToIssuer>
                <relationshipToIssuer>Officer</relationshipToIssuer>
            </relationshipsToIssuer>
        </issuerInfo>
        <securitiesInformation>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <brokerOrMarketmakerDetails>
                <name>Morgan Stanley Smith Barney LLC Executive Financial Services</name>
                <address>
                    <ns2:street1>1 New York Plaza</ns2:street1>
                    <ns2:street2>8th Floor</ns2:street2>
                    <ns2:city>New York</ns2:city>
                    <ns2:stateOrCountry>NY</ns2:stateOrCountry>
                    <ns2:zipCode>10004</ns2:zipCode>
                </address>
            </brokerOrMarketmakerDetails>
            <noOfUnitsSold>42120</noOfUnitsSold>
            <aggregateMarketValue>2743696.80</aggregateMarketValue>
            <noOfUnitsOutstanding>63621472</noOfUnitsOutstanding>
            <approxSaleDate>07/09/2025</approxSaleDate>
            <securitiesExchangeName>NASDAQ</securitiesExchangeName>
        </securitiesInformation>
        <securitiesToBeSold>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <acquiredDate>07/09/2025</acquiredDate>
            <natureOfAcquisitionTransaction>Exercise of Stock Options</natureOfAcquisitionTransaction>
            <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
            <isGiftTransaction>N</isGiftTransaction>
            <amountOfSecuritiesAcquired>42120</amountOfSecuritiesAcquired>
            <paymentDate>07/09/2025</paymentDate>
            <natureOfPayment>Cash</natureOfPayment>
        </securitiesToBeSold>
        <nothingToReportFlagOnSecuritiesSoldInPast3Months>N</nothingToReportFlagOnSecuritiesSoldInPast3Months>
        <securitiesSoldInPast3Months>
            <sellerDetails>
                <name>10b5-1 Sales for HUNTER SMITH</name>
                <address>
                    <ns2:street1>222 Berkeley Street, 12th Floor</ns2:street1>
                    <ns2:city>BOSTON</ns2:city>
                    <ns2:stateOrCountry>MA</ns2:stateOrCountry>
                    <ns2:zipCode>02116</ns2:zipCode>
                </address>
            </sellerDetails>
            <securitiesClassTitle>Common</securitiesClassTitle>
            <saleDate>05/30/2025</saleDate>
            <amountOfSecuritiesSold>23400</amountOfSecuritiesSold>
            <grossProceeds>1437010.85</grossProceeds>
        </securitiesSoldInPast3Months>
        <noticeSignature>
            <noticeDate>07/09/2025</noticeDate>
            <planAdoptionDates>
                <planAdoptionDate>02/28/2025</planAdoptionDate>
            </planAdoptionDates>
            <signature>/s/ Hunter Smith</signature>
        </noticeSignature>
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144
0001636385
XXXXXXXX
LIVE
0001649904
RHYTHM PHARMACEUTICALS, INC.
001-38223
222 Berkeley Street, 12th Floor
BOSTON
MA
02116
8572644280
HUNTER SMITH
Officer
Common
Morgan Stanley Smith Barney LLC Executive Financial Services
1 New York Plaza
8th Floor
New York
NY
10004
42120
2743696.80
63621472
07/09/2025
NASDAQ
Common
07/09/2025
Exercise of Stock Options
Issuer
N
42120
07/09/2025
Cash
N
10b5-1 Sales for HUNTER SMITH
222 Berkeley Street, 12th Floor
BOSTON
MA
02116
Common
05/30/2025
23400
1437010.85
07/09/2025
02/28/2025
/s/ Hunter Smith