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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2011-01-10</periodOfReport>

    <dateOfOriginalSubmission>2011-01-11</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001162324</issuerCik>
        <issuerName>URANERZ ENERGY CORP.</issuerName>
        <issuerTradingSymbol>URZ</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001323911</rptOwnerCik>
            <rptOwnerName>KIRCHNER GERHARD F</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>PO BOX 196</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MONT NEBO</rptOwnerCity>
            <rptOwnerState>A9</rptOwnerState>
            <rptOwnerZipCode>S0J 1X0</rptOwnerZipCode>
            <rptOwnerStateDescription>SASKATCHEWAN, CANADA</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Shares</value>
            </securityTitle>
            <transactionDate>
                <value>2011-01-10</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>30000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>3.73</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>438122</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <remarks>This amended Form 4 is being filed to correct the duplicate reporting of the sale by Dr. Kirchner of 10,000 common shares on January 11, 2011. That sale, which was reported twice in error, has been removed from this report. Additionally, the numbe of securities owned by Dr. Kirchner following the reported transaction has been corrected.</remarks>

    <ownerSignature>
        <signatureName>Gerhard Kirchner</signatureName>
        <signatureDate>2011-01-21</signatureDate>
    </ownerSignature>
</ownershipDocument>
