UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-K/A

AMENDMENT NO. 2

/X/ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended December 31, 2004

or

/ / TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from __________ to __________

Commission file number 0-6890

MECHANICAL TECHNOLOGY INCORPORATED

(Exact name of registrant as specified in its charter)

Registrant's telephone number, including area code: (518) 533-2200

Securities registered pursuant to Section 12(b) of the Act: NONE

Securities registered pursuant to Section 12 (g) of the Act:

Indicate by check mark whether the Registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the Registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes x No ¨

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K (Section 229.405 of this chapter) is not contained herein, and will not be contained, to the best of Registrant's knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K. ¨

Indicate by check mark whether the Registrant is an accelerated filer (as defined in Rule 12b-2 of the Act). Yes x No ¨

The aggregate market value of the voting and non-voting Registrant's common stock held by non-affiliates of the Registrant on June 30, 2004 (based on the last sale price of $5.98 per share for such stock reported by NASDAQ for that date) was approximately $141,233,398.

As of March 9, 2005, the Registrant had 30,610,213 shares of common stock outstanding.

Documents incorporated by reference: NONE

EXPLANATORY NOTE

This Annual Report on Form 10-K/A ("Form 10-K/A") is being filed as Amendment No. 2 to the Registrant's Annual Report on Form 10-K for the fiscal year ended December 31, 2004.  This Form 10-K/A is filed with the Securities and Exchange Commission (the "Commission") solely for the purpose of amending Items 9A and 15 of the filing to include Management's Report on Internal Control Over Financial Reporting, the associated report of PricewaterhouseCoopers LLP on the audit of management's assessment of the effectiveness of the Company's internal control over financial reporting as of December 31, 2004 and Exhibits 23 and 23.3, as well as currently dated certifications.

Unaffected items have not been repeated in this Form 10-K/A.  This Form 10-K/A does not reflect events occurring after the filing of original Form 10-K, and does not modify or update the disclosures therein in any way other than as required to reflect the amendments as described above and set forth below.

Management of the Company is responsible for establishing and maintaining adequate internal control over financial reporting, as that term is defined in Exchange Act Rules 13a-15(f) and 15d-15(f). The Company's internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles.

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

Under the supervision and with the participation of the Company's management, including the principal executive officer and principal financial officer, the Company conducted an evaluation of the effectiveness of its internal control over financial reporting based on the framework in Internal Control-Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission. Based on our evaluation under the framework in Internal Control-Integrated Framework, our management concluded that our internal control over financial reporting was effective as of December 31, 2004.

Our management's assessment of the effectiveness of the Company's internal control over financial reporting as of December 31, 2004 has been audited by PricewaterhouseCoopers LLP, an independent registered public accounting firm, as stated in their report, which is included herein.

Mechanical Technology Incorporated

In our opinion, management's assessment, included in Management's Report on Internal Control Over Financial Reporting appearing under Item 9A, that the Company maintained effective internal control over financial reporting as of December 31, 2004 based on criteria established in Internal Control - Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission (COSO), is fairly stated, in all material respects, based on those criteria. Also, in our opinion, the Company maintained, in all material respects, effective internal control over financial reporting as of December 31, 2004, based on criteria established in Internal Control - Integrated Framework issued by the COSO. The Company's management is responsible for maintaining effective internal control over financial reporting and for its assessment of the effectiveness of internal control over financial reporting. Our responsibility is to express opinions on management's assessment and on the effectiveness of the Company's internal control over financial reporting based on our audit. We conducted our audit in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether effective internal control over financial reporting was maintained in all material respects. An audit includes obtaining an understanding of internal control over financial reporting, evaluating management's assessment, testing and evaluating the design and operating effectiveness of internal control, and performing such other procedures as we consider necessary in the circumstances. We believe that our audit provides a reasonable basis for our opinions.

A company's internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. A company's internal control over financial reporting includes those policies and procedures that (i) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the company; (ii) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and (iii) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of the company's assets that could have a material effect on the financial statements.

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

We have also audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States), the consolidated financial statements of Mechanical Technology Incorporated at December 31, 2004 and 2003, and for each of the three years in the period ended December 31, 2004 and in our report dated March 2, 2005, we expressed an unqualified opinion thereon.

/s/PricewaterhouseCoopers LLP

Albany, New York

April 29, 2005

(a) (1) The financial statements filed herewith are set forth on the Index to Consolidated Financial Statements on page F-1 of the separate financial section which accompanies this Report, which is incorporated herein by reference.

(a) (2) Schedule. The following consolidated financial statement schedule for the years ended December 31, 2004, 2003 and 2002 is included pursuant to Item 15(d):

All other financial statement schedules not listed have been omitted because they are either not required, not applicable, or the information has been included elsewhere in the consolidated financial statements or notes thereto.

The following exhibits are filed as part of this Report:

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.
17. Filed as an Exhibit to the registrant's Form 8-K Report dated May 4, 2004.
18. Filed as an Exhibit to the registrant's Form 10-Q Report for its quarter ended September 30, 2004.
19. Filed as an Exhibit to the registrant's Form 8-K Report dated December 10, 2004.
20. Filed as an Exhibit to the registrant's Form 8-K Report dated December 22, 2004.
21. Filed as an Exhibit to the registrant's Form 10-K Report for the Year ended December 31, 2004.
22. Filed as an Exhibit to the registrant's Amendment No.1 to Form 10-K for the year ended December 31, 2004.

4. In accordance with the requirements of Rule 3-09 of Regulation S-X and as a result of comments received from the Securities and Exchange Commission in connection with a review of our previous filings, separate financial statements for Plug Power Inc. and SatCon Technology Corporation, less than fifty percent owned entities, filed herewith are set forth on their respective Indexes to Financial Statements of their separate financial sections. Such financial sections are filed as Exhibits 99.15.1 and 99.15.2 for Plug Power and SatCon, respectively. Plug Power's fiscal year ended December 31, 2002 and SatCon's unaudited nine months ended June 29, 2002.

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this Amendment No. 2 to Form 10-K on Form 10-K/A to be signed on its behalf by the undersigned, thereunto duly authorized on this 2nd day of May, 2005.

Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.