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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-12-03</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000723458</issuerCik>
        <issuerName>STATE BANCORP INC</issuerName>
        <issuerTradingSymbol>STB</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001223539</rptOwnerCik>
            <rptOwnerName>BRAUN FREDERICK C III</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2 JERICHO PLAZA</rptOwnerStreet1>
            <rptOwnerStreet2>2ND FLOOR, WING C</rptOwnerStreet2>
            <rptOwnerCity>JERICHO</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>11753</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Ex. Vice Pres.</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>State Bancorp,Inc. common stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-12-03</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2629</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>7.63</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>21232.139</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>ISO</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>7.63</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2004-12-03</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F2"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2629</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>2629</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>1996-01-23</value>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2005-01-23</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>STB common</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2629</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeHolding>
            <securityTitle>
                <value>ISO</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>16.52</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>1998-01-27</value>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2006-01-27</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>STB common</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>3651</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3651</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>ISO</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>13.01</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>1999-01-25</value>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2007-01-25</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>STB common</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>3477</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3477</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>ISO</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>10.39</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2000-02-29</value>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2008-02-29</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>STB common</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>3280</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3280</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>ISO</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>12.95</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2001-02-27</value>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2009-02-27</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>STB common</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>9724</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9724</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>ISO</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>15.69</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2002-02-26</value>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2012-02-26</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>STB common</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>6482</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9482</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>ISO</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>17.14</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2003-02-24</value>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2013-02-24</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>STB common</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>5512</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5512</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Acquired upon exercise of incentive stock option.</footnote>
        <footnote id="F2">Exercise of incentive stock option.</footnote>
        <footnote id="F3">These options are subject to a five year schedule (0% the first year and 25% in each of the following years)</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Frederick C. Braun III</signatureName>
        <signatureDate>2004-12-06</signatureDate>
    </ownerSignature>
</ownershipDocument>

