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

    <schemaVersion>X0305</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2012-05-14</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000104918</issuerCik>
        <issuerName>AVISTA CORP</issuerName>
        <issuerTradingSymbol>AVA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001202543</rptOwnerCik>
            <rptOwnerName>HOLLEY RICK R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>AVISTA CORP</rptOwnerStreet1>
            <rptOwnerStreet2>1411 E MISSION AVE</rptOwnerStreet2>
            <rptOwnerCity>SPOKANE</rptOwnerCity>
            <rptOwnerState>WA</rptOwnerState>
            <rptOwnerZipCode>99220-3727</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2012-05-14</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1862</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>25.77</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5019</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Shares issued under the Long Term Incentive Plan as an award of stock for director compensation.  The price per share (per the LTIP) is the closing price of May 11, 2012.</footnote>
        <footnote id="F2">Shares issues as a part of Mr. Holley's director retainer.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Rick R. Holley</signatureName>
        <signatureDate>2012-05-14</signatureDate>
    </ownerSignature>
</ownershipDocument>
[{"type": "4", "sequence": "1", "filename": "primary_doc.xml", "description": "PRIMARY DOCUMENT", "secsgml_size_bytes": 3394}]
X0305
4
2012-05-14
0
0000104918
AVISTA CORP
AVA
0001202543
HOLLEY RICK R
AVISTA CORP
1411 E MISSION AVE
SPOKANE
WA
99220-3727
1
0
0
0
Common Stock
2012-05-14
4
A
0
1862
25.77
A
5019
D
Shares issued under the Long Term Incentive Plan as an award of stock for director compensation.  The price per share (per the LTIP) is the closing price of May 11, 2012.
Shares issues as a part of Mr. Holley's director retainer.
/s/ Rick R. Holley
2012-05-14