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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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<SEC-DOCUMENT>0001167178-09-000002.txt : 20090420
<SEC-HEADER>0001167178-09-000002.hdr.sgml : 20090420
<ACCEPTANCE-DATETIME>20090417102953
ACCESSION NUMBER:		0001167178-09-000002
CONFORMED SUBMISSION TYPE:	D
PUBLIC DOCUMENT COUNT:		1
ITEM INFORMATION:		Rule 506
FILED AS OF DATE:		20090417
DATE AS OF CHANGE:		20090417
EFFECTIVENESS DATE:		20090417

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			A123 SYSTEMS, INC.
		CENTRAL INDEX KEY:			0001167178
		STANDARD INDUSTRIAL CLASSIFICATION:	MISCELLANEOUS ELECTRICAL MACHINERY, EQUIPMENT & SUPPLIES [3690]
		IRS NUMBER:				043583876
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		D
		SEC ACT:		1933 Act
		SEC FILE NUMBER:	021-39833
		FILM NUMBER:		09755453

	BUSINESS ADDRESS:	
		STREET 1:		ARSENAL ON THE CHARLES
		STREET 2:		321 ARSENAL STREET
		CITY:			WATERTOWN
		STATE:			MA
		ZIP:			02472
		BUSINESS PHONE:		6177785700

	MAIL ADDRESS:	
		STREET 1:		ARSENAL ON THE CHARLES
		STREET 2:		321 ARSENAL STREET
		CITY:			WATERTOWN
		STATE:			MA
		ZIP:			02472

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	A123 SYSTEMS INC
		DATE OF NAME CHANGE:	20020212
</SEC-HEADER>
<DOCUMENT>
<TYPE>D
<SEQUENCE>1
<FILENAME>primary_doc.xml
<TEXT>
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<?xml version="1.0"?>
<edgarSubmission>

    <schemaVersion>X0301</schemaVersion>

    <submissionType>D</submissionType>

    <testOrLive>LIVE</testOrLive>

    <primaryIssuer>
        <cik>0001167178</cik>
        <entityName>A123 SYSTEMS, INC.</entityName>
        <issuerAddress>
            <street1>ARSENAL ON THE CHARLES</street1>
            <street2>321 ARSENAL STREET</street2>
            <city>WATERTOWN</city>
            <stateOrCountry>MA</stateOrCountry>
            <zipCode>02472</zipCode>
        </issuerAddress>
        <issuerPhoneNumber>6177785700</issuerPhoneNumber>
        <issuerPreviousNameList>
            <previousName>A123 SYSTEMS INC</previousName>
        </issuerPreviousNameList>
        <jurisdictionOfInc>DE</jurisdictionOfInc>
        <entityType>Corporation</entityType>
        <yearOfInc>
            <overFiveYears>true</overFiveYears>
        </yearOfInc>
    </primaryIssuer>

    <relatedPersonsList>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Gilbert</firstName>
                <middleName>Neal</middleName>
                <lastName>Riley, Jr.</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>The Arsenal on the Charles</street1>
                <street2>321 Arsenal Street, 3rd Floor</street2>
                <city>Watertown</city>
                <stateOrCountry>MA</stateOrCountry>
                <zipCode>02472</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>David</firstName>
                <middleName>P.</middleName>
                <lastName>Vieau</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>The Arsenal on the Charles</street1>
                <street2>321 Arsenal Street, 3rd Floor</street2>
                <city>Watertown</city>
                <stateOrCountry>MA</stateOrCountry>
                <zipCode>02472</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Gururaj</firstName>
                <middleName></middleName>
                <lastName>Deshpande</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>The Arsenal on the Charles</street1>
                <street2>321 Arsenal Street, 3rd Floor</street2>
                <city>Watertown</city>
                <stateOrCountry>MA</stateOrCountry>
                <zipCode>02472</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
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        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Jeffrey</firstName>
                <middleName></middleName>
                <lastName>McCarthy</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>The Arsenal on the Charles</street1>
                <street2>321 Arsenal Street, 3rd Floor</street2>
                <city>Watertown</city>
                <stateOrCountry>MA</stateOrCountry>
                <zipCode>02472</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Paul</firstName>
                <middleName></middleName>
                <lastName>Jacobs</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>The Arsenal on the Charles</street1>
                <street2>321 Arsenal Street, 3rd Floor</street2>
                <city>Watertown</city>
                <stateOrCountry>MA</stateOrCountry>
                <zipCode>02472</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Gary</firstName>
                <middleName></middleName>
                <lastName>Haroian</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>The Arsenal on the Charles</street1>
                <street2>321 Arsenal Street, 3rd Floor</street2>
                <city>Watertown</city>
                <stateOrCountry>MA</stateOrCountry>
                <zipCode>02472</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Michael</firstName>
                <middleName></middleName>
                <lastName>Rubino</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>The Arsenal on the Charles</street1>
                <street2>321 Arsenal Street, 3rd Floor</street2>
                <city>Watertown</city>
                <stateOrCountry>MA</stateOrCountry>
                <zipCode>02472</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Executive Officer</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Arthur</firstName>
                <middleName></middleName>
                <lastName>Goldstein</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>The Arsenal on the Charles</street1>
                <street2>321 Arsenal Street, 3rd Floor</street2>
                <city>Watertown</city>
                <stateOrCountry>MA</stateOrCountry>
                <zipCode>02472</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
        <relatedPersonInfo>
            <relatedPersonName>
                <firstName>Mark</firstName>
                <middleName></middleName>
                <lastName>Little</lastName>
            </relatedPersonName>
            <relatedPersonAddress>
                <street1>The Arsenal on the Charles</street1>
                <street2>321 Arsenal Street, 3rd floor</street2>
                <city>Watertown</city>
                <stateOrCountry>MA</stateOrCountry>
                <zipCode>02472</zipCode>
            </relatedPersonAddress>
            <relatedPersonRelationshipList>
                <relationship>Director</relationship>
            </relatedPersonRelationshipList>
            <relationshipClarification></relationshipClarification>
        </relatedPersonInfo>
    </relatedPersonsList>

    <offeringData>
        <industryGroup>
            <industryGroupType>Other Technology</industryGroupType>
        </industryGroup>
        <issuerSize>
            <revenueRange>Decline to Disclose</revenueRange>
        </issuerSize>
        <federalExemptionsExclusions>
            <item>06</item>
        </federalExemptionsExclusions>
        <typeOfFiling>
            <newOrAmendment>
                <isAmendment>false</isAmendment>
            </newOrAmendment>
            <dateOfFirstSale>
                <value>2009-04-03</value>
            </dateOfFirstSale>
        </typeOfFiling>
        <durationOfOffering>
            <moreThanOneYear>false</moreThanOneYear>
        </durationOfOffering>
        <typesOfSecuritiesOffered>
            <isEquityType>true</isEquityType>
        </typesOfSecuritiesOffered>
        <businessCombinationTransaction>
            <isBusinessCombinationTransaction>false</isBusinessCombinationTransaction>
            <clarificationOfResponse></clarificationOfResponse>
        </businessCombinationTransaction>
        <minimumInvestmentAccepted>0</minimumInvestmentAccepted>
        <salesCompensationList></salesCompensationList>
        <offeringSalesAmounts>
            <totalOfferingAmount>69260134</totalOfferingAmount>
            <totalAmountSold>69260134</totalAmountSold>
            <totalRemaining>0</totalRemaining>
            <clarificationOfResponse></clarificationOfResponse>
        </offeringSalesAmounts>
        <investors>
            <hasNonAccreditedInvestors>false</hasNonAccreditedInvestors>
            <totalNumberAlreadyInvested>23</totalNumberAlreadyInvested>
        </investors>
        <salesCommissionsFindersFees>
            <salesCommissions>
                <dollarAmount>0</dollarAmount>
            </salesCommissions>
            <findersFees>
                <dollarAmount>0</dollarAmount>
            </findersFees>
            <clarificationOfResponse></clarificationOfResponse>
        </salesCommissionsFindersFees>
        <useOfProceeds>
            <grossProceedsUsed>
                <dollarAmount>0</dollarAmount>
            </grossProceedsUsed>
            <clarificationOfResponse></clarificationOfResponse>
        </useOfProceeds>
        <signatureBlock>
            <authorizedRepresentative>false</authorizedRepresentative>
            <signature>
                <issuerName>A123 SYSTEMS, INC.</issuerName>
                <signatureName>/s/ David Vieau</signatureName>
                <nameOfSigner>David Vieau</nameOfSigner>
                <signatureTitle>President and Chief Executive Officer</signatureTitle>
                <signatureDate>2009-04-15</signatureDate>
            </signature>
        </signatureBlock>
    </offeringData>
</edgarSubmission>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----