<SUBMISSION>
<ACCESSION-NUMBER>0001209191-11-047272
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20110908
<FILING-DATE>20110909
<DATE-OF-FILING-DATE-CHANGE>20110909
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>Mehta Nikhil Atul
<CIK>0001502610
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-33710
<FILM-NUMBER>111083579
</FILING-VALUES>
<MAIL-ADDRESS>
<STREET1>C/O CLEAN DIESEL TECHNOLOGIES, INC.
<STREET2>4567 TELEPHONE ROAD, SUITE 206
<CITY>VENTURA
<STATE>CA
<ZIP>93003
</MAIL-ADDRESS>
</REPORTING-OWNER>
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>CLEAN DIESEL TECHNOLOGIES INC
<CIK>0000949428
<ASSIGNED-SIC>3564
<IRS-NUMBER>061393453
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>4567 TELEPHONE ROAD
<STREET2>SUITE 206
<CITY>VENTURA
<STATE>CA
<ZIP>93003
<PHONE>805 639 9458
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>4567 TELEPHONE ROAD
<STREET2>SUITE 206
<CITY>VENTURA
<STATE>CA
<ZIP>93003
</MAIL-ADDRESS>
</ISSUER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>c22302_4x0.xml
<DESCRIPTION>MAIN DOCUMENT DESCRIPTION
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0304</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2011-09-08</periodOfReport>

    <issuer>
        <issuerCik>0000949428</issuerCik>
        <issuerName>CLEAN DIESEL TECHNOLOGIES INC</issuerName>
        <issuerTradingSymbol>CDTI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001502610</rptOwnerCik>
            <rptOwnerName>Mehta Nikhil Atul</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CLEAN DIESEL TECHNOLOGIES, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>4567 TELEPHONE ROAD, SUITE 206</rptOwnerStreet2>
            <rptOwnerCity>VENTURA</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>93003</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Financial Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2011-09-08</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>13334</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>13334</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>13334</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Each restricted stock unit (RSU) represents a contingent right to receive one share of CDTI common stock.</footnote>
        <footnote id="F2">The RSU vests as to 100% on the sixth business day from September 8, 2011, the date of grant.  Issuance will occur on vest date. RSUs that have not vested at the time of the reporting person's termination of service, for any or no reason, will be forfeited.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Kristi Cushing for Nikhil Atul Mehta</signatureName>
        <signatureDate>2011-09-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
