-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 nDNMxvclGWjPWplxuaCqIw==

<SEC-DOCUMENT>0000916863-11-000001.txt : 20110104
<SEC-HEADER>0000916863-11-000001.hdr.sgml : 20110104
<ACCEPTANCE-DATETIME>20110104164859
ACCESSION NUMBER:		0000916863-11-000001
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20101231
FILED AS OF DATE:		20110104
DATE AS OF CHANGE:		20110104

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			CAFFERTY PASTORA SAN JUAN
		CENTRAL INDEX KEY:			0001197025

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-11337
		FILM NUMBER:		11506613

	MAIL ADDRESS:	
		STREET 1:		1001 FANNIN ST
		STREET 2:		STE 4000
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77002

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			INTEGRYS ENERGY GROUP, INC.
		CENTRAL INDEX KEY:			0000916863
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTRIC & OTHER SERVICES COMBINED [4931]
		IRS NUMBER:				391775292
		STATE OF INCORPORATION:			WI
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		130 EAST RANDOLPH DRIVE
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60601
		BUSINESS PHONE:		800-699-1269

	MAIL ADDRESS:	
		STREET 1:		130 EAST RANDOLPH DRIVE
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60601

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Integrys Energy Group, Inc.
		DATE OF NAME CHANGE:	20070222

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	WPS RESOURCES CORP
		DATE OF NAME CHANGE:	19940103
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgardoc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-12-31</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000916863</issuerCik>
        <issuerName>INTEGRYS ENERGY GROUP, INC.</issuerName>
        <issuerTradingSymbol>TEG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001197025</rptOwnerCik>
            <rptOwnerName>CAFFERTY PASTORA SAN JUAN</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>130 EAST RANDOLPH DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60601</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0.741</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>by Stk Invest Plan</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7050</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>by Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Phantom Stock Unit</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2010-12-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>25.7678</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>48.51</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>25.7678</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2167.4807</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeHolding>
            <securityTitle>
                <value>Deferred Stock Unit</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F4"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>6173.041</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6173.041</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Stock Option (Right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>47.22</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2002-11-01</value>
            </exerciseDate>
            <expirationDate>
                <value>2012-05-01</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2475</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2475</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Stock Option (Right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>48.57</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2001-11-01</value>
            </exerciseDate>
            <expirationDate>
                <value>2011-05-01</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2475</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2475</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">These phantom stock units convert to common stock on a one-for-one basis.</footnote>
        <footnote id="F2">Unless the participant has selected a later commencement date, distribution of stock and equivalents will commence within 60 days following the end of the calendar year in which occurs the participant's retirement or termination of service.</footnote>
        <footnote id="F3">Unless the participant has selected a later commencement date, distribution of stock and equivalents will commence within 60 days following the end of the calendar year in which occurs the participant's retirement or termination of service.</footnote>
        <footnote id="F4">These deferred stock units convert to common stock on a one-for-one basis.</footnote>
    </footnotes>

    <remarks>Table II reflects dividends paid on Phantom Stock Units and reinvested in additional Phantom Stock Units, and dividends paid on Deferred Stock Units and reinvested in additional Deferred Stock Units under the Company's Deferred Compensation Plan on December 20, 2010.</remarks>

    <ownerSignature>
        <signatureName>By: Dane E. Allen, as Power of Attorney  For: Ms. Cafferty</signatureName>
        <signatureDate>2011-01-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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