<SEC-DOCUMENT>0001808365-25-000005.txt : 20251218
<SEC-HEADER>0001808365-25-000005.hdr.sgml : 20251218
<ACCEPTANCE-DATETIME>20251218161505
ACCESSION NUMBER:		0001808365-25-000005
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20251121
FILED AS OF DATE:		20251218
DATE AS OF CHANGE:		20251218

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Knowles Julius
		CENTRAL INDEX KEY:			0001808365
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-39264
		FILM NUMBER:		251583250

	MAIL ADDRESS:	
		STREET 1:		MASS GENERAL BRIGHAM VENTURES
		STREET 2:		399 REVOLUTION DRIVE, SUITE 999
		CITY:			SOMERVILLE
		STATE:			MA
		ZIP:			02145

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Keros Therapeutics, Inc.
		CENTRAL INDEX KEY:			0001664710
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		ORGANIZATION NAME:           	03 Life Sciences
		EIN:				811173868
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		1050 WALTHAM STREET, SUITE 302
		CITY:			LEXINGTON
		STATE:			MA
		ZIP:			02421
		BUSINESS PHONE:		617-314-6297

	MAIL ADDRESS:	
		STREET 1:		1050 WALTHAM STREET, SUITE 302
		CITY:			LEXINGTON
		STATE:			MA
		ZIP:			02421
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>form4-12182025_041201.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-11-21</periodOfReport>

    <issuer>
        <issuerCik>0001664710</issuerCik>
        <issuerName>Keros Therapeutics, Inc.</issuerName>
        <issuerTradingSymbol>KROS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001808365</rptOwnerCik>
            <rptOwnerName>Knowles Julius</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O KEROS THERAPEUTICS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>1050 WALTHAM STREET, SUITE 302</rptOwnerStreet2>
            <rptOwnerCity>LEXINGTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02421</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>true</isDirector>
            <isOfficer>false</isOfficer>
            <isTenPercentOwner>false</isTenPercentOwner>
            <isOther>false</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-11-21</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>191527</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>17.75</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>150047</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-11-21</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>130494</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>17.75</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>102233</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6441</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Represents shares tendered and accepted for purchase by the Issuer in a cash tender offer commenced by the Issuer on October 20, 2025. The Issuer announced the final results of the tender offer on November 20, 2025.</footnote>
        <footnote id="F2">The securities are held by Partners Innovation Fund, LLC (&quot;PIF I&quot;). Partners Innovation Fund, LLC (&quot;Partners GP I&quot;) is the ultimate general partner of PIF I. The Reporting Person, a member of the board of directors of the Issuer, is a partner of Partners GP I and as a result, may be deemed to share voting and investment power with respect to the shares held by PIF I.</footnote>
        <footnote id="F3">The securities are held by Partners Innovation Fund II, L.P. (&quot;PIF II&quot;). Partners Innovation Fund II, LLC (&quot;Partners GP II&quot;) is the ultimate general partner of PIF II. The Reporting Person, a member of the board of directors of the Issuer, is a partner of Partners GP II and as a result, may be deemed to share voting and investment power with respect to the shares held by PIF II.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Keith Regnante, Attorney-in-Fact</signatureName>
        <signatureDate>2025-12-18</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
