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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2013-03-19</periodOfReport>

    <dateOfOriginalSubmission>2013-03-21</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000728385</issuerCik>
        <issuerName>Midwest Energy Emissions Corp.</issuerName>
        <issuerTradingSymbol>MEEC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001524386</rptOwnerCik>
            <rptOwnerName>MacPherson Richard</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>34 CEDARBANK TERRACE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>HALIFAX</rptOwnerCity>
            <rptOwnerState>A5</rptOwnerState>
            <rptOwnerZipCode>B3P 2TR</rptOwnerZipCode>
            <rptOwnerStateDescription>NOVA SCOTIA, CANADA</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2013-03-19</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>55500</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.88</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>17569061</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By 3253517 Nova Scotia Limited</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2013-03-19</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>250000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.43</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>17319061</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By 3253517 Nova Scotia Limited</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">On March 19, 2013, 3253517 Nova Scotia Limited (the &quot;Transferor&quot;) effected a transfer of 55,500 and 250,000 shares of common stock to two transferees in private transactions. The consideration for the transfer of 55,500 shares was CDN $50,000 payable $25,000 in cash and $25,000 in services previously rendered to the Transferor. The 250,000 shares have been transferred pursuant to and as consideration for an executed Release relating to, among other things, services previously rendered. The 250,000 shares have been valued at the market price of the common stock on the date of transfer.</footnote>
        <footnote id="F2">The Reporting Person is the controlling principal of 3253517 Nova Scotia Limited.</footnote>
        <footnote id="F3">This form is being filed to amend this reported transaction only in order to reflect the disposition of 55,500 shares at a price of $0.88 per share.  The original filing indicated 55,000 shares at a price of $0.89 per share.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Richard MacPherson</signatureName>
        <signatureDate>2013-07-19</signatureDate>
    </ownerSignature>
</ownershipDocument>
