<?xml version="1.0"?>

<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2003-09-25</periodOfReport>


    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000095301</issuerCik>
        <issuerName>SEQUA CORP /DE/</issuerName>
        <issuerTradingSymbol>SQAA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001179589</rptOwnerCik>
            <rptOwnerName>LEITNER HOWARD M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O SEQUA CORP</rptOwnerStreet1>
            <rptOwnerStreet2>200 PARK AVENUE, 44TH FL</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10166</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Senior Vice President, Finance</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>

        <derivativeTransaction>
            <securityTitle>
                <value>Employee stock option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>41.7</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2003-09-25</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>6000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2004-09-25</value>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2008-09-24</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>6000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>

    </derivativeTable>

    <footnotes>
        <footnote id="F1">Granted pursuant to Sequa Corporation 1998 Key Employees Stock Option Plan.  The option vests in three equal annual installments beginning on September 25, 2004.</footnote>
    </footnotes>


    <ownerSignature>
        <signatureName>/s/ Howard M. Leitner</signatureName>
        <signatureDate>2003-09-29</signatureDate>
    </ownerSignature>

</ownershipDocument>
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X0201
4
2003-09-25
0
0000095301
SEQUA CORP /DE/
SQAA
0001179589
LEITNER HOWARD M
C/O SEQUA CORP
200 PARK AVENUE, 44TH FL
NEW YORK
NY
10166
0
1
0
0
Senior Vice President, Finance
Employee stock option (right to buy)
41.7
2003-09-25
4
A
0
6000
0
A
2004-09-25
2008-09-24
Class A Common Stock
6000
6000
D
Granted pursuant to Sequa Corporation 1998 Key Employees Stock Option Plan.  The option vests in three equal annual installments beginning on September 25, 2004.
/s/ Howard M. Leitner
2003-09-29