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

    <schemaVersion>X0201</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2004-01-30</periodOfReport>

    <dateOfOriginalSubmission>2003-09-02</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001001868</issuerCik>
        <issuerName>FIBERNET TELECOM GROUP INC\</issuerName>
        <issuerTradingSymbol>FTGX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000948046</rptOwnerCik>
            <rptOwnerName>DEUTSCHE BANK AG\</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>TAUNUSANLAGE 12 D-60325</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>FRANKFURT AM MAIN</rptOwnerCity>
            <rptOwnerState>I8</rptOwnerState>
            <rptOwnerZipCode></rptOwnerZipCode>
            <rptOwnerStateDescription>GERMANY (WEST)</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common</value>
            </securityTitle>
            <transactionDate>
                <value>2004-01-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>X</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>184846</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.001</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4603610</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Warrants</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.001</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2004-01-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>X</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>184964</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.001</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2004-01-30</value>
            </exerciseDate>
            <expirationDate>
                <value>2007-11-11</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock,Par Value $0.001</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>184846</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>777880</value>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The number of shares of Common Stock received following the exercise of Warrants was less than the number of Warrants exercised because the exercise of Warrants was cashless. The difference in shares (118 shares) was calculated by dividing the cost of exercising the 184,964 Warrants ($184.96) by the relevant market price of the Common Stock as determined by the issuer on January 30, 2004, which was the date of exercise ($1.57).</footnote>
        <footnote id="F2">The exercise of Warrants was cashless and, as a result, the number of shares of Common Stock received following the exercise was less than the number of Warrants exercised. The difference in shares (118) was calculated by dividing the cost of the exercising the 184,964 Warrants ($118.96) by the relevant market price of the Common Stock as determined bt the issuer on January 30,2004, which was the date of exercise ($1.57).</footnote>
        <footnote id="F3">A 1 for 30 reverse stock split previously effected by the Issuer was not taken into account when preparing the Previous Filings, the Reporting Person's beneficial ownership positions were overstated by a factor of 30.  The Reporting Person's aggregate beneficial ownership positions (See Table I, Column 5; and Table II, Column 9 in each Form 4) for the Previous Filings are hereby restated as follows, please see below comments.</footnote>
        <footnote id="F4">A 1 for 30 reverse stock split previously effected by the Issuer was not taken into account when preparing the Previous Filings, the Reporting Person's beneficial ownership positions were overstated by a factor of 30.  The Reporting Person's aggregate beneficial ownership positions (See Table I, Column 5; and Table II, Column 9 in each Form 4) for the Previous Filings are hereby restated as follows, please see below comments.</footnote>
    </footnotes>

    <remarks>This Amendment is made to the Forms 4 filed by the Reporting Person on February 2, 2004; October 16, 2003; and September 10, 2003 (collectively, the &quot;Previous Filings&quot;); and is intended to correct unintentional overstatements of the Reporting Person's beneficial ownership of the Issuer's non-derivative and derivative securities, as stated in the Previous Filings.  In particular, because a 1 for 30 reverse stock split previously effected by the Issuer was not taken into account when preparing the Previous Filings, the Reporting Person's beneficial ownership positions were overstated by a factor of 30.  The Reporting Person's aggregate beneficial ownership positions (See Table I, Column 5; and Table II, Column 9 in each Form 4) for the Previous Filings are hereby restated as follows:

1.   Form 4 filed on February 2, 2004
Non-Derivative Securities Beneficially Owned:  4,603,610 common shares
Derivative Securities Beneficially Owned:  777,880 warrants

2.   Form 4 filed on October 16, 2003
Non-Derivative Securities Beneficially Owned:  4,597,448 common shares
Derivative Securities Beneficially Owned:  784,046 warrants

3.   Form 4 filed on September 10, 2003
Non-Derivative Securities Beneficially Owned:  4,591,432 common shares
Derivative Securities Beneficially Owned:  790,189 warrants</remarks>

    <ownerSignature>
        <signatureName>Jeffrey A. Ruiz, Attorney-In-Fact</signatureName>
        <signatureDate>2004-03-04</signatureDate>
    </ownerSignature>
</ownershipDocument>

