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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2006-05-09</periodOfReport>

    <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>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001354805</rptOwnerCik>
            <rptOwnerName>MHR Capital Partners Master Account LP</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>0001301392</rptOwnerCik>
            <rptOwnerName>MHR Institutional Advisors II 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>0001277742</rptOwnerCik>
            <rptOwnerName>MHR FUND MANAGEMENT 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>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2006-05-09</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>266890</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>8.26</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3123626</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2006-05-09</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>31554</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>8.26</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>424818</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2006-05-09</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>187979</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>8.26</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>187979</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2006-05-09</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>473577</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>8.26</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>473577</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">These securities are held for the account of MHR Capital Partners Master Account LP, an Anguilla, British West Indies limited partnership (&quot;Master Account&quot;). MHR Advisors LLC, a Delaware limited liability company (&quot;Advisors&quot;), is the general partner of Master Account. 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 securites held for the account of Master Account. MHR Fund Management LLC (&quot;Fund Management&quot;) is a Delaware limited liability company that has an investment management agreement with Master Account pursuant to which it has the power to vote or direct the vote and to dispose or to direct the disposition of the Securities and, accordingly, Fund Management may be deemed to beneficially own the Securities held for the account of Master Account.</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 securitites held for the account of Capital Partners (100). Fund Management has an investment management agreement with Capital Partners (100) pursuant to which it has the power to vote or direct the vote and to dispose or to direct the disposition of the Securities and, accordingly, Fund Management may be deemed to beneficially own the Securities held for the account of Capital Partners (100).</footnote>
        <footnote id="F3">These securities are held for the account of MHR Institutional Partners II LP, a Delaware limited partnership (&quot;Institutional Partners II&quot;). MHR Institutional Advisors II LLC, a Delaware limited liability company (&quot;Institutional Advisors&quot;), is the general partner of Institutional Partners II. Dr. Rachesky is the managing member of Institutional Advisors. In such capacity, Dr. Rachesky may be deemed to be the beneficial owner of the securities held for the account of Institutional Partners II. Fund Management has an investment management agreement with Institutional Partners II pursuant to which it has the power to vote or direct the vote and to dispose or to direct the disposition of the Securities and, accordingly, Fund Management may be deemed to beneficially own the Securities held for the account of Institutional Partners II.</footnote>
        <footnote id="F4">These securities are hold for the account of MHR Institutional Partners IIA LP, a Delaware limited partnership (&quot;Institutional Partners IIA&quot;). Institutional Advisors is the general partner of Institutional Partners IIA. Dr. Rachesky is the managing member of Institutional Advisors. In such capacity, Dr. Rachesky may be deemed to be the beneficial owner of the securities held for the account of Institutional Partners IIA. Fund Management has an investment management agreement with Institutional Partners IIA pursuant to which it has the power to vote or direct the vote and to dispose or to direct the disposition of the Securities and, accordingly, Fund Management may be deemed to beneficically own the Securities held for the account of Insititutional Partners IIA.</footnote>
    </footnotes>

    <remarks>Remarks:

The filing of this statement shall not be deemed an admission that 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.

Exhibit List:
Exhibit 99- Joint Filer Information</remarks>

    <ownerSignature>
        <signatureName>/s/ Mark H. Rachesky, MD</signatureName>
        <signatureDate>2006-05-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
