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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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<SEC-DOCUMENT>0001140361-09-008885.txt : 20090402
<SEC-HEADER>0001140361-09-008885.hdr.sgml : 20090402
<ACCEPTANCE-DATETIME>20090402180654
ACCESSION NUMBER:		0001140361-09-008885
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20090331
FILED AS OF DATE:		20090402
DATE AS OF CHANGE:		20090402

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SHEPPARD HOWARD B
		CENTRAL INDEX KEY:			0001283288

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-33443
		FILM NUMBER:		09729184

	MAIL ADDRESS:	
		STREET 1:		6001 BOLLINGER CANYON ROAD E-2080
		CITY:			SAN RAMON
		STATE:			CA
		ZIP:			94583-2324

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			DYNEGY INC.
		CENTRAL INDEX KEY:			0001379895
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTRIC SERVICES [4911]
		IRS NUMBER:				205653152
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		1000 LOUISIANA STREET, SUITE 5800
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77002
		BUSINESS PHONE:		(713) 507-6400

	MAIL ADDRESS:	
		STREET 1:		1000 LOUISIANA STREET, SUITE 5800
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77002

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Dynegy Inc..
		DATE OF NAME CHANGE:	20070404

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Dynegy Acquisition, Inc..
		DATE OF NAME CHANGE:	20070403

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Dynegy Acquisition, Inc.
		DATE OF NAME CHANGE:	20061102
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-03-31</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001379895</issuerCik>
        <issuerName>DYNEGY INC.</issuerName>
        <issuerTradingSymbol>DYN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001283288</rptOwnerCik>
            <rptOwnerName>SHEPPARD HOWARD B</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>538 BLAIR AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>PIEDMONT</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94611</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Phantom Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-03-31</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>12368.37</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A common stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>12368.37</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>29588.96</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">These shares are held in a rabbi trust and are deemed to be phantom stock that are convertible on a 1-for-1 basis.</footnote>
        <footnote id="F2">Reflects shares of phantom stock issued to the Reporting Person pursuant to the Dynegy Inc. Deferred Compensation Plan for Certain Directors, as amended, a Rule 16b-3 Plan with the issuer.  The shares of phantom stock were issued in connection with the Reporting Person's director compensation for the first quarter of 2009, and the number of shares of phantom stock issued with respect to the quarter was calculated based on the stock price of the issuer's Class A common stock of $1.41 (rounded) on March 31, 2009, the last trading day of the quarter.</footnote>
        <footnote id="F3">Upon termination of the Reporting Person's service as a director, the shares of phantom stock become payable, at the election of the Reporting Person, in a lump sum payment or in monthly, quarterly or annual installment payments following such termination.  The shares of phantom stock are payable in cash or in shares of the issuer's Class A common stock.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Heidi D. Lewis, Attorney-in-Fact</signatureName>
        <signatureDate>2009-04-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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