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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2004-04-14</periodOfReport>

    <dateOfOriginalSubmission>2004-06-17</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000761237</issuerCik>
        <issuerName>IMCOR PHARMACEUTICAL CO</issuerName>
        <issuerTradingSymbol>ICPHC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001262294</rptOwnerCik>
            <rptOwnerName>FLEMING JONATHAN</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O OXFORD BIOSCIENCE PARTNERS</rptOwnerStreet1>
            <rptOwnerStreet2>222 BERKELEY STREET, SUITE 1650</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001286541</rptOwnerCik>
            <rptOwnerName>OBP MANAGEMENT IV LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>222 BERKELEY STREET, SUITE 1650</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02116</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>2004-04-14</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>5500000</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.4</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>11981482</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Oxford Bioscience Partners IV L.P. and MRNA Fund II L.P.</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-04-14</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>9750870</value>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.4</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>21732352</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Oxford Bioscience Partners IV L.P. and MRNA Fund II L.P.</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-04-19</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>22022417</value>
                    <footnoteId id="F4"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.4</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>43754769</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Oxford Bioscience Partners IV L.P. and MRNA Fund II L.P.</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Revolving Convertible Senior Secured Promissory Notes</value>
            </securityTitle>
            <transactionDate>
                <value>2004-04-14</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3900348</value>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.4</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Oxford Bioscience Partners IV L.P. and MRNA Fund II L.P.</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Secured Promissory Notes</value>
            </securityTitle>
            <transactionDate>
                <value>2004-04-19</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>8800966.96</value>
                    <footnoteId id="F4"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.4</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Oxford Bioscience Partners IV L.P. and MRNA Fund II L.P.</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Warrants to purchase common stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.50</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2004-04-14</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2750001</value>
                    <footnoteId id="F5"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2004-04-14</value>
            </exerciseDate>
            <expirationDate>
                <value>2009-04-14</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2750001</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2750001</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Oxford Bioscience Partners IV L.P. and MRNA Fund II L.P.</value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Jonathan Fleming is the general partner of OBP Management IV L.P., which is the general partner of both Oxford Bioscience Partners IV L.P. (&quot;Oxford&quot;) and MRNA Fund II L.P (&quot;MRNA&quot;).  As such Mr. Fleming and OBP Management IV L.P. disclaim beneficial ownership except to the extent of their pecuniary interests.</footnote>
        <footnote id="F2">On April 14, 2004, Oxford agreed to purchase 568,678 shares of common stock and MRNA agreed to purchase 5,706 shares of common stock, each at a price of $0.75 per share.  On April 19, 2004, the first of two closings occurred and the shares mentioned in the previous sentence were issued.  On June 30, 2004, the second closing occurred and the entire transaction (including the April 19, 2004 and June 30, 2004 closings) was re-priced at $0.40 per share.  Based on the revised terms, an aggregate of 4,925,616 shares were issued and include both those shares issued in connection with the second closing and the additional shares resulting from the re-pricing of the first closing.  Of the 4,925,616 shares issued on June 30, 2004, 4,876,687 shares were issued to Oxford and 48,929 shares were issued to MRNA.</footnote>
        <footnote id="F3">On April 14, 2004, Oxford and MRNA agreed to convert convertible notes in the aggregate amount of $3,900,348 at a conversion price of $0.75 per share.  This conversion resulted in the acquisition of 5,148,802 shares by Oxford and the acquisition of 51,662 shares by MRNA.  On June 30, 2004, in connection with the second closing and the re-pricing of shares at $0.40 per share, an aggregate of an additional 4,550,406 shares were issued.  Of the additional 4,550,406 shares, Oxford acquired 4,505,202 shares and MRNA acquired 45,204 shares.</footnote>
        <footnote id="F4">On June 30, 2004, in connection with the second closing, Oxford and MRNA converted secured notes in the aggregate of $8,800,966.96.  Of the aggregate amount of $8,800,966.96, Oxford converted $8,726,766.55 at a price of $0.40 per share, which resulted in its acquisition of 21,816,916 shares of common stock.  Of the aggregate of $8,800,966.96, MRNA converted $74,200.41 at a conversion price of $0.40 per share, which resulted in its acquisition of 185,501 shares of common stock.</footnote>
        <footnote id="F5">On April 19, 2004, Oxford acquired warrants to purchase 284,339 shares of common stock and MRNA acquired warrants to purchase 2,853 shares of common stock.  In connection with the second closing on June 30, 2004, Oxford acquired warrants to purchase an additional 2,438,344 shares of common stock and MRNA acquired warrants to purchase an additional 24,465 shares of common stock.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Alexia Pearsall, under power of attorney for Jonathan Fleming</signatureName>
        <signatureDate>2004-07-02</signatureDate>
    </ownerSignature>
</ownershipDocument>

