SecProbe.io

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549

       DIVISION OF
CORPORATION FINANCE

Mail Stop 6010
September 19, 2007

VIA U.S. MAIL AND FACSIMILE (518.533.2201)

Ms. Cynthia A. Scheuer
Chief Financial Officer
Mechanical Technology Incorporated
431 New Karner Road
Albany, New York 12205

 Re: Mechanical Technology Incorporated
  Form 10-K for the fiscal year ended December 31, 2006
  Filed March 16, 2007
File No. 000-06890

Dear Ms. Scheuer:

We have reviewed your filing and have the following comments.  We have limited our
review to only your financial statements and related disclosures and do not intend to expand our
review to other portions of your documents.  Wh ere indicated, we think you should revise your
document in response to these comments.  If you disagree, we will consider your explanation as
to why our comment is inapplicable or a revisi on is unnecessary.  Please be as detailed as
necessary in your explanation.  In  some of our comments, we may ask you to provide us with
information so we may better understand your disclo sure.  After reviewing this information, we
may raise additional comments.

Please understand that the purpose of our re view process is to assist you in your
compliance with the applicable disclosure requir ements and to enhance the overall disclosure in
your filings.  We look forward to working with  you in these respects.  We welcome any
questions you may have about our comments or on any other aspect of our review.  Feel free to
call us at the telephone numbers lis ted at the end of  this letter.

Ms. Cynthia A. Scheuer
Mechanical Technology Incorporated
September 19, 2007 Page 2

Form 10-K for the Fiscal Year Ended December 31, 2006

Consolidated Financial Statements, page F-1

Note 10.  Shareholders’ Equity, page F-21

Plug Power Shares, page F-22

1. With a view towards disclosure, please te ll us how you accounted for and calculated the
amount of the loss on derivative of $7,173,000 and the gain on the sale of the Plug Power common shares of $9,635,000.  Please reconc ile with the amounts shown on the
statement of operations for fiscal 2005 for loss on derivative and gain on sale of securities
available for sale.

Note 15.  Derivatives, page F-32

2. Please tell us and revise future filings to disclose the method and significant assumptions
used to value the derivatives at inception and at each balan ce sheet date.  Please provide
us with a reconciliation of your response to  the amount reflected as a derivative liability
of $0 and $3,664,000 as of December 31, 2005 and 2006.

Note 13.  Stock Based Compensation, page F-25

3. With respect to footnote C, please tell us and disclose in future filings the interest rate used.  Per paragraph A25 of SFAS 123R, the risk-free interest rate is the implied yield
currently available on U.S. Treasury zero-coupon  issues with a remaining term equal to
the expected term used as the assumption in the model.

4. You disclose that “APB Opinion No. 25 re quires no recognition of compensation expense
for most of the stock-based compensati on arrangements provided by the Company,
namely, broad-based employee option grants wher e the exercise price is equal to or not
less than 85% of the market va lue at the date of grant.”  We note similar disclosure for
the MTI Micro Option Plan on page F-30.  Pleas e tell us how this policy is consistent
with paragraph 10 of APB 25.  Cite the accounting literature you relied upon.

Ms. Cynthia A. Scheuer
Mechanical Technology Incorporated
September 19, 2007 Page 3

As appropriate, please respond to these comments  within 10 business days or tell us when
you will provide us with a response.  Please furn ish a letter that keys your responses to our
comments and provides any requested information.  De tailed letters greatly f acilitate our review.
Please understand that we may have additional co mments after reviewing your responses to our
comments.

We urge all persons who are responsible for th e accuracy and adequacy of the disclosure
in the filing to be certain that the filing includes all information re quired under the Securities
Exchange Act of 1934 and that they have provi ded all information investors require for an
informed investment decision.  Since the compa ny and its management are in possession of all
facts relating to a company’s disclosure, they are responsible for the acc uracy and adequacy of
the disclosures they have made.

In connection with responding to our comment s, please provide, in writing, a statement
from the company acknowledging that:

⋅ the company is responsible for the adequacy  and accuracy of the disclosure in the
filing;

⋅ staff comments or changes to disclosure  in response to staff comments do not
foreclose the Commission from taking any action with respect to the filing; and

⋅ the company may not assert staff comments as a defense in any proceeding initiated
by the Commission or any person under the federal securities laws of the United States.

In addition, please be advise d that the Division of Enfo rcement has access to all
information you provide to the sta ff of the Division of Corporati on Finance in our review of your
filing or in response to our comments on your filing.

You may contact Kate Tillan, Assistant Chie f Accountant, at (202)  551-3604 or me at
(202) 551-3554 if you have any questions regardi ng comments on the financial statements and
related matters.  You may also contact Martin James; Senior Assistant Chief Accountant, at (202) 551-3604 with any other questions.

        S i n c e r e l y ,

        A n g e l a  C r a n e
        B r a n c h  C h i e f

Ms. Cynthia A. Scheuer
Mechanical Technology Incorporated
September 19, 2007 Page 4