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

    <schemaVersion>X0201</schemaVersion>

    <documentType>5</documentType>

    <periodOfReport>2003-12-31</periodOfReport>

    <form3HoldingsReported>0</form3HoldingsReported>

    <form4TransactionsReported>0</form4TransactionsReported>

    <issuer>
        <issuerCik>0000921847</issuerCik>
        <issuerName>HUDSON CITY BANCORP INC</issuerName>
        <issuerTradingSymbol>HCBK</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001206760</rptOwnerCik>
            <rptOwnerName>OLSZEWSKI VERONICA A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>WEST 80 CENTURY ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>PARAMUS</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>07652</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Senior Vice President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock, par value $0.01per share</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>27480</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock, par value $0.01per share</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5535</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By PIB</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock, par value $0.01per share</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4142</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By ESOP</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock, par value $0.01per share</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>16002</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Stock Options (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>13.495</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F4"/>
                <footnoteId id="F5"/>
            </exerciseDate>
            <expirationDate>
                <value>2012-01-09</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>45000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>45000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Stock Options (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>6.9375</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F4"/>
                <footnoteId id="F5"/>
            </exerciseDate>
            <expirationDate>
                <value>2010-01-13</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>36000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>36000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Award to reporting person of 11,300 shares of Common Stock was made pursuant to the Hudson City Bancorp, Inc. 2000 Recognition and Retention Plan (&quot;RRP&quot;), which the stockholders approved at a Special Meeting of Stockholders of Hudson City Bancorp, Inc. held on January 13, 2000 (Special Meeting&quot;), effective January 10, 2002.  On April 20, 2002, 2,260 shares vested and became directly owned by the reporting person.  The shares awarded pursuant to the RRP were adjusted to reflect a 2-for-1 stock split on June 17, 2002 and on April 20, 2003, 4,520 shares vested and became directly owned by the reporting person.  The unvested shares will vest at a rate of 4,520 shares per year, on each of April 20, 2004, 2005 and 2006.  Previous award to the reporting person of 17,400 shares of common stock pursuant to RRP was made by the Board of Directors, effective January 10, 2000.    (This footnote continues in number 2 below.)</footnote>
        <footnote id="F2">Footnote 1 continued:   On each of April 20, 2001 and 2002, 3,480 shares vested and became directly owned by the reporting person.  Pursuant to the 2-for-1 stock split on June 17, 2002, an additional 6,960 shares will vest on each of April 20, 2004 and 2005.  Such shares will be held in trust by DB Alex Brown, LLC, as trustee for the RRP, until vesting.</footnote>
        <footnote id="F3">The reporting person holds the shares through the Hudson City Savings Bank's Profit Incentive Bonus Plan as of December 31, 2003.</footnote>
        <footnote id="F4">Grant to reporting person of options to buy 22,500 shares of Common Stock pursuant to the Hudson City Bancorp, Inc. 2000 Stock Option Plan was made by the Board of Directors, effective January 10, 2002.  The options awarded to the reporting person were adjusted to reflect a 2-for-1 stock split on June 17, 2002. On January 13, 2003 and 2004, 9,000 options vested and became exercisable.  The unvested options will vest and become exercisable at a rate to buy 9,000 shares per year on each of January 13, 2005, 2006 and 2007.  Previous grant to the reporting person of options to buy 30,000 shares of common stock was made pursuant to the Hudson City Bancorp, Inc. 2000 Stock Option Plan that was approved by stockholders at the Special Meeting.  Options to buy 6,000 shares of common stock vested and became exercisable on each of January 13, 2001 and 2002.  (This footnote continues in number 5 below.)</footnote>
        <footnote id="F5">Footnote 4 continued: The options awarded to the reporting were adjusted to reflect a 2-for-1 stock split on June 17, 2002 and 12,000 options vested and  became exercisable on January 13, 2003 and 2004.  The 12,000 unvested options will vest and become exercisable on January 13, 2005.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Louis J. Beierle, Attorney-in-Fact</signatureName>
        <signatureDate>2004-02-10</signatureDate>
    </ownerSignature>
</ownershipDocument>

