<SUBMISSION>
<ACCESSION-NUMBER>0001209191-09-019005
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20090327
<FILING-DATE>20090331
<DATE-OF-FILING-DATE-CHANGE>20090331
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>Varanasi Ramani
<CIK>0001460224
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-33958
<FILM-NUMBER>09720615
</FILING-VALUES>
<MAIL-ADDRESS>
<STREET1>342 BUNKER HILL ST. #5D
<CITY>CHARLESTOWN
<STATE>MA
<ZIP>02129
</MAIL-ADDRESS>
</REPORTING-OWNER>
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>RXI PHARMACEUTICALS CORP
<CIK>0001390478
<ASSIGNED-SIC>2834
<IRS-NUMBER>000000000
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>60 PRESCOTT  STREET
<CITY>WORCESTER
<STATE>MA
<ZIP>01605
<PHONE>508-767-3861
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>60 PRESCOTT  STREET
<CITY>WORCESTER
<STATE>MA
<ZIP>01605
</MAIL-ADDRESS>
</ISSUER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc4.xml
<DESCRIPTION>FORM 4 SUBMISSION
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-03-27</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001390478</issuerCik>
        <issuerName>RXI PHARMACEUTICALS CORP</issuerName>
        <issuerTradingSymbol>RXII</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001460224</rptOwnerCik>
            <rptOwnerName>Varanasi Ramani</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O RXI PHARMACEUTICALS CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>60 PRESCOTT STREET</rptOwnerStreet2>
            <rptOwnerCity>WORCESTER</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>01605</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>VP, Business Development</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>4.98</value>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-03-27</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>14760</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2019-03-27</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>14760</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>14760</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>4.98</value>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-03-27</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>85240</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F4"/>
            </exerciseDate>
            <expirationDate>
                <value>2019-03-27</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>85240</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>100000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Granted pursuant to the RXi Pharmaceuticals Corporation 2007 Incentive Plan.</footnote>
        <footnote id="F2">Per share.</footnote>
        <footnote id="F3">The options will vest in equal installments of 4,920 shares on each of December 25, 2010, December 25, 2011 and December 25, 2011.</footnote>
        <footnote id="F4">The options will vest in the following increments on the following dates: 6,250 shares on June 25, 2009, 6,250 shares on September 25, 2009, 6,250 shares on December 25, 2009, 6,250 shares on March 25, 2010, 6,250 shares on June 25, 2010, 6,250 shares on September 25, 2010, 1,330 shares on December 25, 2010, 6,250 shares on  shares on March 25, 2011, 6,250 shares on June 25, 2011, 6,250 shares on September 25, 2011, 1,330 shares on December 25, 2011, 6,250 shares on March 25, 2012, 6,250 shares on June 25, 2012, 6,250 shares on September 25, 2012, 1,330 shares on December 25, 2012 and 6, 250 shares on March 25, 2013.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Ramani Varanasi</signatureName>
        <signatureDate>2009-03-31</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
