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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-08-18</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001014669</issuerCik>
        <issuerName>STERLING CHEMICALS INC</issuerName>
        <issuerTradingSymbol>SCHI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001259927</rptOwnerCik>
            <rptOwnerName>LASRY MARC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O AVENUE CAPITAL</rptOwnerStreet1>
            <rptOwnerStreet2>535 MADISON AVE 15TH</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-08-18</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1200</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>5.0292</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>411401</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote.</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The securities reported in this Form 4 were held directly by Avenue Special Situations Fund II, L.P., Delaware limited partnership (&quot;SSII&quot;).  The Reporting Person is (i) the Managing Member of Avenue Capital Management II GenPar, LLC, which is the general partner of Avenue Capital Management II, L.P., which is the registered investment adviser to SSII and (ii) the Managing Member of the Managing Member of the general partner of SSII.  The Reporting Person is deemed to be the indirect beneficial owner of the securities reported by reason of his ability to direct the vote and/or disposition of such securities, and his pecuniary interest in such shares (within the meaning of Rule 16a-1(a)(2) under the Securities Exchange Act of 1934, as amended) was a fractional interest in such amount. The Reporting Person disclaims beneficial ownership of any and all such amounts in excess of such actual pecuniary interest.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Eric Ross as Attorney-in-Fact for Marc Lasry</signatureName>
        <signatureDate>2010-08-19</signatureDate>
    </ownerSignature>
</ownershipDocument>
