<SUBMISSION>
<ACCESSION-NUMBER>0001209191-09-003962
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20090115
<FILING-DATE>20090120
<DATE-OF-FILING-DATE-CHANGE>20090120
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>DiPalma Stephen J.
<CIK>0001426479
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-33958
<FILM-NUMBER>09535548
</FILING-VALUES>
<BUSINESS-ADDRESS>
<PHONE>617-767-3861
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>C/O RXI PHARMACEUTICALS CORPORATION
<STREET2>50 PRESCOTT STREET
<CITY>WORCESTER
<STATE>MA
<ZIP>01605
</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>2009-01-15</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001426479</rptOwnerCik>
            <rptOwnerName>DiPalma Stephen J.</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>CFO, EVP, Secretary</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>4.19</value>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-01-15</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>47000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2019-01-15</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>47000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>166428</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>4.19</value>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-01-15</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>36218</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F4"/>
            </exerciseDate>
            <expirationDate>
                <value>2019-01-15</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>36218</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>202646</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 vest in the following increments on the following dates: 2,937 shares on April 15, 2009, 2,938 shares on July 15, 2009, 2,937 shares on October 15, 2009, 2,938 on January 15, 2010, 2,937 shares on April 15, 2010, 2,938 shares on July 15, 2010, 2,937 shares on October 15, 2010, 2,938 on January 15, 2011, 2,937 shares on April 15, 2011, 2,938 shares on July 15, 2011, 2,937 shares on October 15, 2011, 2,938 on January 15, 2012, 2,937 shares on April 15, 2012, 2,938 shares on July 15, 2012, 2,937 shares on October 15, 2012, and 2,938 on January 15, 2013, so that all of the options will be fully vested on January 15, 2013.</footnote>
        <footnote id="F4">The options vest in the following increments on the following dates: 2,263 shares on April 15, 2009, 2,264 shares on July 15, 2009, 2,263 shares on October 15, 2009, 2,264 on January 15, 2010, 2,264 shares on April 15, 2010, 2,263 shares on July 15, 2010, 2,264 shares on October 15, 2010, 2,264 on January 15, 2011, 2,263 shares on April 15, 2011, 2,264 shares on July 15, 2011, 2,263 shares on October 15, 2011, 2,264 on January 15, 2012, 2,264 shares on April 15, 2012, 2,263 shares on July 15, 2012, 2,264 shares on October 15, 2012, and 2,264 on January 15, 2013, so that all of the options will be fully vested on January 15, 2013.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Stephen J. DiPalma</signatureName>
        <signatureDate>2009-01-20</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
