<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>
<periodOfReport>2003-10-21</periodOfReport>
<notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0000029924</issuerCik>
        <issuerName>DOW JONES &amp; CO INC</issuerName>
        <issuerTradingSymbol>DJ</issuerTradingSymbol>
</issuer>
<reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001056567</rptOwnerCik>
            <rptOwnerName>STEELE ELIZABETH</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O HEMENWAY &amp; BARNES</rptOwnerStreet1>
            <rptOwnerStreet2>60 STATE STREET</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02109</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector>
<isOfficer>0</isOfficer>
<isTenPercentOwner>0</isTenPercentOwner>
<isOther>0</isOther>
<officerTitle></officerTitle>
<otherText></otherText>
</reportingOwnerRelationship>
</reportingOwner>
<nonDerivativeTable>
<nonDerivativeTransaction>
<securityTitle>
<value>Common</value>
<footnoteId id="F1"/>
</securityTitle>
<transactionDate>
<value>2003-10-21</value>
</transactionDate>
<deemedExecutionDate>
</deemedExecutionDate>
<transactionCoding>
<transactionFormType>4</transactionFormType>
<transactionCode>S</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionTimeliness>
<value></value>
</transactionTimeliness>
<transactionAmounts>
<transactionShares>
<value>2000</value>
</transactionShares>
<transactionPricePerShare>
<value>50.1144</value>
</transactionPricePerShare>
<transactionAcquiredDisposedCode>
<value>D</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>174000</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>I</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value>Being shares owned as beneficiary of the Jane Cook 1941 Trust of which I am also a trustee</value>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeTransaction>
<nonDerivativeTransaction>
<securityTitle>
<value>Common</value>
<footnoteId id="F1"/>
</securityTitle>
<transactionDate>
<value>2003-10-22</value>
</transactionDate>
<deemedExecutionDate>
</deemedExecutionDate>
<transactionCoding>
<transactionFormType>4</transactionFormType>
<transactionCode>S</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionTimeliness>
<value></value>
</transactionTimeliness>
<transactionAmounts>
<transactionShares>
<value>2000</value>
</transactionShares>
<transactionPricePerShare>
<value>49.5405</value>
</transactionPricePerShare>
<transactionAcquiredDisposedCode>
<value>D</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>172000</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>I</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value>Being shares owned as beneficiary of the Jane Cook 1941 Trust of which I am also a trustee</value>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeTransaction>
<nonDerivativeHolding>
<securityTitle>
<value>Common</value>
<footnoteId id="F1"/>
</securityTitle>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>318773</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>I</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value>Being shares owned by the Elizabeth Steele Revocable Trust dated 11/27/01</value>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeHolding>
<nonDerivativeHolding>
<securityTitle>
<value>Common</value>
<footnoteId id="F1"/>
</securityTitle>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>768841</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>I</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value>Being shares owned by my sister in the Martha S. Robes Dow Jones Trust of which I am a trustee</value>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeHolding>
<nonDerivativeHolding>
<securityTitle>
<value>Common</value>
<footnoteId id="F1"/>
</securityTitle>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>2117511</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>I</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value>Being shares of common stock which may be obtained upon conversion of Class B Common Stock</value>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeHolding>
<nonDerivativeHolding>
<securityTitle>
<value>Class B</value>
<footnoteId id="F1"/>
</securityTitle>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>372787</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>I</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value>Being shares owned by the Elizabeth Steele Revocable Trust dated 11/27/01</value>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeHolding>
<nonDerivativeHolding>
<securityTitle>
<value>Class B</value>
<footnoteId id="F1"/>
</securityTitle>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>1371173</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>I</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value>Being shares owned as beneficiary of the Jane Cook 1941 Trust of which I am also a trustee</value>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeHolding>
<nonDerivativeHolding>
<securityTitle>
<value>Class B</value>
<footnoteId id="F1"/>
</securityTitle>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>373551</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>I</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value>Being shares owned by my sister in the Martha S. Robes Dow Jones Trust of which I am a trustee</value>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeHolding>
</nonDerivativeTable>
<footnotes>
<footnote id="F1">The filing of this statement shall not be construed as an admission that the reporting person is, for the purposes of Section 16 of the Securities and Exchange Act of 1934, the beneficial owner of shares covered by this Statement.</footnote>
</footnotes>
<remarks></remarks>
<ownerSignature>
<signatureName>/s/ Elizabeth Steele</signatureName>
<signatureDate>2003-10-23</signatureDate>
</ownerSignature>
</ownershipDocument>

