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

    <schemaVersion>X0202</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2005-03-31</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000805326</issuerCik>
        <issuerName>EMISPHERE TECHNOLOGIES INC</issuerName>
        <issuerTradingSymbol>EMIS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001194368</rptOwnerCik>
            <rptOwnerName>RACHESKY MARK H MD</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>40 WEST 57TH STREET</rptOwnerStreet1>
            <rptOwnerStreet2>24TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10019</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001284082</rptOwnerCik>
            <rptOwnerName>MHR ADVISORS LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>40 WEST 57TH STREET</rptOwnerStreet1>
            <rptOwnerStreet2>24TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10019</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001019190</rptOwnerCik>
            <rptOwnerName>MHR CAPITAL PARTNERS LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>40 WEST 57TH STREEET</rptOwnerStreet1>
            <rptOwnerStreet2>24TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10019</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2856736</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>393264</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Warrants (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>4.00</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2005-03-31</value>
            </exerciseDate>
            <expirationDate>
                <value>2010-03-31</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>823387</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Warrants (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>4.00</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2005-03-31</value>
            </exerciseDate>
            <expirationDate>
                <value>2010-03-31</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>114114</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">These securities are held for the account of MHR Capital Partners LP, a Delaware limited partnership (&quot;Capital Partners&quot;).  MHR Advisors LLC, a Delaware limited liability company (&quot;Advisors&quot;), is the general partner of Capital Partners.  Mark H. Rachesky, M.D. (&quot;Dr. Rachesky&quot;) is the managing member of Advisors.  In such capacity, Dr. Rachesky may be deemed to be the beneficial owner of the securities held for the account of Capital Partners.</footnote>
        <footnote id="F2">These securities are held for the account of MHR Capital Partners (100) LP, a Delaware limited partnership (&quot;Capital Partners (100)&quot;).  Advisors is the general partner of Capital Partners (100).  Dr. Rachesky is the managing member of Advisors.  In such capacity, Dr. Rachesky may be deemed to be the beneficial owner of the securities held for the account of Capital Partners (100).</footnote>
    </footnotes>

    <remarks>The filing of this statement shall not be deemed an admission that the any of the Reporting Persons is the beneficial owner of any securities not held directly for his or its account for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise.</remarks>

    <ownerSignature>
        <signatureName>Mark H. Rachesky, M.D.</signatureName>
        <signatureDate>2005-04-08</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>MHR Advisors LLC, by Hal Goldstein as Vice President</signatureName>
        <signatureDate>2005-04-08</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>MHR Capital Partners LP, by MHR Advisors LLC as General Partner, by Hal Goldstein as Vice President</signatureName>
        <signatureDate>2005-04-08</signatureDate>
    </ownerSignature>
</ownershipDocument>
