-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 M31oBnSYvwZgZNwBJBD+EGqSmXGd7QeG3LO6PlM5QcADqUq5XvL6AGMyMbEkFh0D
 gYiF4hI5e78IfkS90sGarA==

<SEC-DOCUMENT>0000941138-08-000145.txt : 20080819
<SEC-HEADER>0000941138-08-000145.hdr.sgml : 20080819
<ACCEPTANCE-DATETIME>20080819132833
ACCESSION NUMBER:		0000941138-08-000145
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20080814
FILED AS OF DATE:		20080819
DATE AS OF CHANGE:		20080819

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			UNISOURCE ENERGY CORP
		CENTRAL INDEX KEY:			0000941138
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTRIC SERVICES [4911]
		IRS NUMBER:				860786732
		STATE OF INCORPORATION:			AZ
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		ONE SOUTH CHURCH AVENUE
		STREET 2:		SUITE 100
		CITY:			TUCSON
		STATE:			AZ
		ZIP:			85701
		BUSINESS PHONE:		520-571-4000

	MAIL ADDRESS:	
		STREET 1:		ONE SOUTH CHURCH AVENUE, SUITE 100
		STREET 2:		P.O. BOX 711
		CITY:			TUCSON
		STATE:			AZ
		ZIP:			85702

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			FRANCESCONI LOUISE
		CENTRAL INDEX KEY:			0001194786

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-13739
		FILM NUMBER:		081027053

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		781-522-3000

	MAIL ADDRESS:	
		STREET 1:		870 WINTER STREET
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02451
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0203</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2008-08-14</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000941138</issuerCik>
        <issuerName>UNISOURCE ENERGY CORP</issuerName>
        <issuerTradingSymbol>UNS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001194786</rptOwnerCik>
            <rptOwnerName>FRANCESCONI LOUISE</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1 S. CHURCH AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 201</rptOwnerStreet2>
            <rptOwnerCity>TUCSON</rptOwnerCity>
            <rptOwnerState>AZ</rptOwnerState>
            <rptOwnerZipCode>85701</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</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes></footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Raymond S. Heyman, Attorney-in-Fact</signatureName>
        <signatureDate>2008-08-19</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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