<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2007-05-22</periodOfReport>

    <issuer>
        <issuerCik>0000778164</issuerCik>
        <issuerName>Pacific Ethanol, Inc.</issuerName>
        <issuerTradingSymbol>PEIX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001321936</rptOwnerCik>
            <rptOwnerName>Jones William L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>5711 N. WEST AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>FRESNO,</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>93711</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

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                <value>Common Stock</value>
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                </transactionShares>
                <transactionPricePerShare>
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                <transactionAcquiredDisposedCode>
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                </transactionShares>
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                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
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        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
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                <transactionAcquiredDisposedCode>
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                <transactionAcquiredDisposedCode>
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                <transactionAcquiredDisposedCode>
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    </nonDerivativeTable>

    <footnotes></footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ William L. Jones</signatureName>
        <signatureDate>2007-05-23</signatureDate>
    </ownerSignature>
</ownershipDocument>
