<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2013-12-06</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000320017</issuerCik>
        <issuerName>NeoStem, Inc.</issuerName>
        <issuerTradingSymbol>NBS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001368570</rptOwnerCik>
            <rptOwnerName>Wei Eric</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O NEOSTEM, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>420 LEXINGTON AVENUE, SUITE 350</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10170</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.001 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2013-12-06</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>434</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>6.35</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2253084</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.001 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2013-12-09</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>12096</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>6.37</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2240988</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">These securities are held as to 2,240,988 shares of Common Stock by RimAsia Capital Partners L.P., a Cayman Islands exempted limited partnership (&quot;RimAsia LP&quot;), and as to 3,000 shares of Common Stock by RimAsia Capital Partners Manager, Ltd.,, a Cayman Islands exempted company (&quot;Rim Asia Manager&quot;) respectively.</footnote>
        <footnote id="F2">RimAsia Capital Partners GP, L.P., a Cayman Islands exempted limited partnership (&quot;RimAsia GP&quot;), is the general partner of RimAsia LP. RimAsia Manager is the Fund Manager of RimAsia GP and the Manager of RimAsia LP. Mr. Wei is the managing partner of RimAsia LP, an indirect partner of RimAsia GP, a director of RimAsia Capital Partners GP, Ltd. and a director of RimAsia Manager. As a result, Mr. Wei may be deemed to have sole power to vote certain of the securities held by RimAsia LP and RimAsia Manager. Mr. Wei disclaims beneficial ownership of such securities, except to the extent of his pecuniary interest therein, and the inclusion of these securities shall not be deemed an admission of beneficial ownership of all of the reported securities for purposes of Section 16 of the Securities Exchange Act or for any other purpose.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Eric H.C. Wei, By: /s/ Catherine M. Vaczy, Esq., Attorney-in-Fact</signatureName>
        <signatureDate>2013-12-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
