-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 GUnNKoWDQ5R/BEm7op6M38VbAYrbm893bPuo8uzJmigck74CUxHqIErH4inDkdjg
 afiPrYccsG+uPp/dQQmNng==

<SEC-DOCUMENT>0000064463-04-000010.txt : 20040413
<SEC-HEADER>0000064463-04-000010.hdr.sgml : 20040413
<ACCEPTANCE-DATETIME>20040413114015
ACCESSION NUMBER:		0000064463-04-000010
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040412
FILED AS OF DATE:		20040413

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			STERNLIGHT BENO
		CENTRAL INDEX KEY:			0001251274

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-06890
		FILM NUMBER:		04729919

	MAIL ADDRESS:	
		STREET 1:		123 PARTRIDGE RUN
		CITY:			SCHENECTADY
		STATE:			NY
		ZIP:			12309

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MECHANICAL TECHNOLOGY INC
		CENTRAL INDEX KEY:			0000064463
		STANDARD INDUSTRIAL CLASSIFICATION:	MEASURING & CONTROLLING DEVICES, NEC [3829]
		IRS NUMBER:				141462255
		STATE OF INCORPORATION:			NY
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		431 NEW KARNER ROAD
		STREET 2:		BUILDING #4
		CITY:			ALBANY
		STATE:			NY
		ZIP:			12205
		BUSINESS PHONE:		5185332200

	MAIL ADDRESS:	
		STREET 1:		431 NEW KARNER ROAD
		STREET 2:		BUILDING #4
		CITY:			ALBANY
		STATE:			NY
		ZIP:			12205
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-04-12</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000064463</issuerCik>
        <issuerName>MECHANICAL TECHNOLOGY INC</issuerName>
        <issuerTradingSymbol>MKTY</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001251274</rptOwnerCik>
            <rptOwnerName>STERNLIGHT BENO</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>123 PARTRIDGE RUN</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SCHENECTADY</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>12309</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>2004-04-12</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>50000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>6</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>483561</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>200970</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Immediate Family</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The sales of common stock reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 22, 2004.</footnote>
        <footnote id="F2">These shares are held by Lisa Sternlicht, his wife as custodian for Aaron Sternlicht, his son.  Dr. Sternlicht disclaims beneficial ownership of these shares.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Cynthia A. Scheuer as Attorney in Fact for Dr. Beno Sternlicht</signatureName>
        <signatureDate>2004-04-13</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----
