<SUBMISSION>
<ACCESSION-NUMBER>0000007694-03-000161
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20030915
<FILING-DATE>20030917
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>ASHLAND INC
<CIK>0000007694
<ASSIGNED-SIC>5160
<IRS-NUMBER>610122250
<STATE-OF-INCORPORATION>KY
<FISCAL-YEAR-END>0930
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>50 E. RIVERCENTER BOULEVARD
<CITY>COVINGTON
<STATE>KY
<ZIP>41012
<PHONE>6068153333
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>50 E. RIVERCENTER BOULEVARD
<CITY>COVINGTON
<STATE>KY
<ZIP>41012
</MAIL-ADDRESS>
<FORMER-COMPANY>
<FORMER-CONFORMED-NAME>ASHLAND OIL INC
<DATE-CHANGED>19920703
</FORMER-COMPANY>
<FORMER-COMPANY>
<FORMER-CONFORMED-NAME>ASHLAND OIL & REFINING CO
<DATE-CHANGED>19700806
</FORMER-COMPANY>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>PFEIFFER JANE C
<CIK>0001026062
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-02918
<FILM-NUMBER>03899839
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>REPUBLIC BANK CENTER
<STREET2>700 LOUISIANNA, SUITE 3920
<CITY>HOUSTON
<STATE>TX
<ZIP>77002
<PHONE>6063293333
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>REPUBLIC BANK CENTER
<STREET2>700 LOUISIANNA, SUITE 3920
<CITY>HOUSTON
<STATE>TX
<ZIP>77002
</MAIL-ADDRESS>
</REPORTING-OWNER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>

<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2003-09-15</periodOfReport>


    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000007694</issuerCik>
        <issuerName>ASHLAND INC</issuerName>
        <issuerTradingSymbol>ash</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001026062</rptOwnerCik>
            <rptOwnerName>PFEIFFER JANE C</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1050 BEACH ROAD</rptOwnerStreet1>
            <rptOwnerStreet2>APT. 10</rptOwnerStreet2>
            <rptOwnerCity>VERO BEACH</rptOwnerCity>
            <rptOwnerState>FL</rptOwnerState>
            <rptOwnerZipCode>32963</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>

        <derivativeTransaction>
            <securityTitle>
                <value>Common Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2003-09-15</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F2"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>51</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>33.67</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>51</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>15238</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>

    </derivativeTable>

    <footnotes>
        <footnote id="F1">Converts to common stock on a one-for-one basis.</footnote>
        <footnote id="F2">Common Stock Units acquired pursuant to Ashland's Deferred Compensation Plan for Non-Employee Directors as of 9-15-03, payable in cash or stock upon termination of service and exempt under Rule 16b-3.  (One (1) common stock unit in the Deferred Compensation Plan for Non-Employee Directors is the equivalent of one (1) share of Ashland Common Stock)</footnote>
        <footnote id="F3">Common Stock Units acquired pursuant to Ashland's Deferred Compensation Plan for Non-Employee Directors as of 9-15-03, payable in cash or stock upon termination of service and exempt under Rule 16b-3.  (One (1) common stock unit in the Deferred Compensation Plan for Non-Employee Directors is the equivalent of one (1) share of Ashland Common Stock)</footnote>
        <footnote id="F4">Common Stock Units acquired pursuant to Ashland's Deferred Compensation Plan for Non-Employee Directors as of 9-15-03, payable in cash or stock upon termination of service and exempt under Rule 16b-3.  (One (1) common stock unit in the Deferred Compensation Plan for Non-Employee Directors is the equivalent of one (1) share of Ashland Common Stock)</footnote>
    </footnotes>


    <ownerSignature>
        <signatureName>M. Craig Hall, by Power of Attorney</signatureName>
        <signatureDate>2003-09-17</signatureDate>
    </ownerSignature>

</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
