If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933 check the following box: x

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ¨

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ¨

If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ¨

If delivery of the prospectus is expected to be made pursuant to Rule 434, please check the following box. ¨

_________________

The registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until this Registration Statement shall become effective on such date as the Commission, acting pursuant to said Section 8(a), may determine.

EXPLANATORY NOTE

This Amendment No.2 to the Registrant's Registration Statement on Form S-1 (File No. 333-121868) is being filed solely for the purpose of filing Exhibit 23.4 herewith, and no change or additions are being made hereby to the prospectus which forms a part of this Registration Statement. Accordingly, the prospectus has been omitted from this filing.

Except for the SEC registration fee and the Nasdaq listing fee, all expenses are estimated. All such expenses will be paid by the Registrant.

Pursuant to the statutes of the State of New York, a director or officer of a corporation is entitled, under specified circumstances, to indemnification by the corporation against reasonable expenses, including attorney's fees, incurred by him/her in connection with the defense of a civil or criminal proceeding to which he/she has been made, or threatened to be made, a party by reason of the fact that he/she was such director or officer. In certain circumstances, indemnity is provided against judgments, fines and amounts paid in settlement. In general, indemnification is available where the director or officer acted in good faith, for a purpose he/she reasonably believed to be in the best interests of the corporation. Specific court approval is required in some cases. The foregoing statement is subject to the detailed provisions of Sections 715, 717 and 721-725 of the New York Business Corporation Law.

Under provisions of Mechanical Technology's Amended and Restated Certificate of Incorporation, Mechanical Technology shall indemnify any person who was or is a party or is threatened to be made a party to any threatened, pending or completed action, proceeding or suit (including one by or in the right of Mechanical Technology to procure a judgment in its favor), whether civil or criminal, by reason of the fact that he, his testator or interstate is or was a director or officer of Mechanical Technology, or is or was serving any other corporation, partnership, joint venture, trust, employee benefit plan or other enterprise in any capacity at the request of Mechanical Technology, against judgments, fines, amounts paid in settlement and expenses, including attorneys' fees, actually incurred as a result of or in connection with any such action, proceeding or suit, or any appeal therefrom, if such director or officer acted in good faith for a purpose which he reasonably believed to be in or not opposed to the best interests of Mechanical Technology, and, in criminal actions or proceedings, in which he had no reasonable cause to believe that his conduct was unlawful; provided, however, that no indemnification shall be made to or on behalf of any director or officer if a judgment or other final adjudication adverse to the director or officer establishes that his acts were committed in bad faith or were the result of active and deliberate dishonesty and were material to the cause of action so adjudicated, or that he personally gained a financial profit or other advantage to which he was not legally entitled.

The directors and officers of Mechanical Technology are covered by insurance policies indemnifying against certain liabilities, including certain liabilities arising under the Securities Act that might be incurred by them in such capacities.

On January 29, 2004 the Company sold 1,418,842 shares of common stock and additional investment rights to Fletcher International, Ltd. in a private sale for an aggregate purchase price of approximately $10 million. On December 22, 2004, Fletcher exercised its right to purchase in a private sale an additional 1,261,829 shares of the Company's common stock for an aggregate purchase price of approximately $8 million. Since the Company failed to meet a registration deadline in connection with the December 2004 private placement, the Company was required to issue an additional 66,413 shares of common stock to Fletcher for no additional consideration under the terms of its agreement with Fletcher. The 66,413 shares were issued April 19, 2005. Each of these Fletcher private placements was exempt from registration under the Securities Act pursuant to Section 4(2) thereof since each was a sale not involving a public offering.

The purchaser in such transactions represented to us that it was an accredited investor, acquiring the securities for investment and not distribution. No underwriters were involved in the foregoing transactions.

(a) The following exhibits are filed as part of this Registration Statement:

Certain exhibits were previously filed (as indicated below) and are incorporated herein by reference. All other exhibits for which no other filing information is given are filed herewith:

10. Filed as an Exhibit (bearing the same exhibit number) to the registrant's Form 10-K Report for the fiscal year ended September 30, 2001.

11. Filed as an Exhibit to the registrant's Form 13-D/A Report dated January 3, 2003.
12. Filed as an Exhibit to the registrant's Form 10-K Report for the year ended December 31, 2002.
13. Filed as an Exhibit to the registrant's Form 10-Q Report for its fiscal quarter ended September 30, 2003.
14. Filed as an Exhibit to the registrant's Form 10-K Report for the year ended December 31, 2003.
15. Filed as an Exhibit to the registrant's Form 8-K Report dated January 27, 2004.
16. Filed as an Exhibit to the registrant's Form 8-K Report dated May 4, 2004.
17. Filed as an Exhibit to the registrant's Form 10-Q Report for its quarter ended September 30, 2004.
18. Filed as an Exhibit to the registrant's Form 8-K Report dated December 10, 2004.
19. Filed as an Exhibit to the registrant's Form 8-K Report dated December 22, 2004.
20. Filed as an Exhibit to the registrant's Form 10-K Report for the year ended December 31, 2004.

* Previously filed.

(b) Schedule. The following financial statement schedule for the years ended December 31, 2004, 2003 and 2002 is included pursuant to Item 16(b):

Report of Independent Registered Public Accounting Firm on Financial Statement Schedule;

Schedule II- Valuation and Qualifying Accounts.

The undersigned registrant does hereby undertake:

Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the registrant pursuant to the provisions described in Item 14 above, or otherwise, the registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Securities Act of 1933, as amended, and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act of 1933, as amended, and will be governed by the final adjudication of such issue.

Pursuant to the requirements of the Securities Act of 1933, the Registrant has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Albany, State of New York, on April 21, 2005.

Pursuant to the requirements of the Securities Act of 1933, this Registration Statement has been signed by the following persons in the capacities and on the dates indicated.

To the Board of Directors and Shareholders

of Mechanical Technology Incorporated

Our audits of the consolidated financial statements referred to in our report dated March 2, 2005, appearing on page F-2 of this Form S-1 of Mechanical Technology Incorporated, also included an audit of the financial statement schedule listed in Item 16(b) of this Form S-1. In our opinion, this financial statement schedule presents fairly, in all material respects, the information set forth therein when read in conjunction with the related consolidated financial statements.

/s/PricewaterhouseCoopers LLP

Albany, New York

March 2, 2005

Includes accounts written off as uncollectible and recoveries.

Includes accounts written off as uncollectible and recoveries.