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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2005-06-30</periodOfReport>

    <dateOfOriginalSubmission>2005-06-30</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000897893</issuerCik>
        <issuerName>PEERLESS SYSTEMS CORP</issuerName>
        <issuerTradingSymbol>PRLS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001033453</rptOwnerCik>
            <rptOwnerName>COLE LOUIS C</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>PEERLESS SYSTEMS CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>2381 ROSECRANS AVE</rptOwnerStreet2>
            <rptOwnerCity>EL SEGUNDO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90245</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>STOCK OPTION (RIGHT TO BUY)</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>3.8</value>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2005-06-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>10000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2015-06-30</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>COMMON STOCK</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>10000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">THIS AMENDMENT TO FORM 4 IS FILED SOLELY FOR THE PURPOSE OF CORRECTING THE EXERCISE PRICE OF THE DERIVATIVE SECURITY.  THE EXERCISE PRICE WAS ORIGINALLY REPORTED AS $3.82.  THE CORRECT EXERCISE PRICE IS $3.80.</footnote>
        <footnote id="F2">TWENTY-FIVE PERCENT (25%) OF THE SHARES SUBJECT TO SUCH OPTION SHALL VEST AND BECOME EXERCISABLE ON JUNE 30, 2006 (THE COMPLETION OF ONE YEAR OF SERVICE MEASURED FROM THE GRANT DATE).  THE BALANCE OF THE SHARES SUBJECT TO SUCH OPTION SHALL VEST AND BECOME EXERCISABLE IN A SERIES OF THIRTY-SIX (36) SUCCESSIVE EQUAL MONTHLY INSTALLMENTS UPON COMPLETION OF EACH ADDITIONAL MONTH OF SERVICE UNTIL ALL OF THE OPTIONS ARE VESTED.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>ELLIOT M. SHIRWO, ATTORNEY-IN-FACT</signatureName>
        <signatureDate>2005-09-26</signatureDate>
    </ownerSignature>
</ownershipDocument>
