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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2003-02-12</periodOfReport>

    <dateOfOriginalSubmission>2005-08-23</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001134878</rptOwnerCik>
            <rptOwnerName>HIGGS DENNIS LYLE</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>SUITE 1410</rptOwnerStreet1>
            <rptOwnerStreet2>800 WEST PENDER STREET</rptOwnerStreet2>
            <rptOwnerCity>VANCOUVER</rptOwnerCity>
            <rptOwnerState>A1</rptOwnerState>
            <rptOwnerZipCode>V6C 2V6</rptOwnerZipCode>
            <rptOwnerStateDescription>BRITISH COLUMBIA, CANADA</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Shares of common stock</value>
            </securityTitle>
            <transactionDate>
                <value>2003-02-12</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1875000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.001</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1875000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See note(1)</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">(1) Consists of 375,000 shares held in the name of Senate Equities Corp., which is wholly owned by Menace Capital Corp., which is in turn wholly owned by Dennis Higgs, and 1,500,000 shares held in the name of Senate Capital Group Inc., which is wholly owned by Dennis Higgs.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Dennis Higgs</signatureName>
        <signatureDate>2005-09-21</signatureDate>
    </ownerSignature>
</ownershipDocument>
