SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549
             ----------------------------------------------------

                   AMENDMENT NO. 1 ON FORM 10-K/A TO FORM 10-K

(mark one)
[ X ]   Annual Report Pursuant to Section 13 or 15(d) of the Securities Exchange
        Act of 1934 for the fiscal year ended October 2, 1999.

[   ]   Transition Report Pursuant to Section 13 or 15(d) of the Securities
        Exchange Act of 1934.

                         Commission file number 1-13572

                            THERMO ECOTEK CORPORATION
             (Exact name of Registrant as specified in its charter)

Delaware                                             04-3072335
(State or other jurisdiction of
incorporation or organization)            (I.R.S. Employer Identification No.)

245 Winter Street
Waltham, Massachusetts                                           02454-9046
(Address of principal executive offices)                         (Zip Code)

             Registrant's telephone number, including area code: (781) 622-1000

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

          Title of each class         Name of exchange on which registered
     Common Stock, $.10 par value           American Stock Exchange

             Securities registered pursuant to Section 12(g) of the Act:
                                      None

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, and (2) has been subject to the filing requirements for
at least the past 90 days. Yes [ X ] No [ ]

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

The aggregate market value of the voting stock held by nonaffiliates of the
Registrant as of October 29, 1999, was approximately $15,823,000.

As of October 29, 1999, the Registrant had 35,967,902 shares of Common Stock
outstanding.

                       DOCUMENTS INCORPORATED BY REFERENCE

Portions of the Registrant's Annual Report to Shareholders for the fiscal year
ended October 2, 1999, are incorporated by reference into Parts I and II.



<PAGE>
                                                   FORM 10-K/A

                                     PART IV

Item 14.     Exhibits, Financial Statement Schedules, and Reports on Form 8-K

(c)     Exhibits

        13   Annual Report to Shareholders for the fiscal year ended October
             2, 1999 (only those portions incorporated herein by reference).

        23   Consent of Arthur Andersen LLP.

        27   Restated Financial Data Schedule for the fiscal year ended
             October 2, 1999.

        27.1 Restated Financial Data Schedule for the fiscal year ended
             October 3, 1998.

        27.2 Restated Financial Data Schedule for the fiscal year ended
             September 27, 1997.

             Attached is Exhibit 13 of the Registrant's Form 10-K for the year
             ended October 2, 1999. The Registrant's financial statements have
             been restated to reflect a decision by the Registrant's parent
             company, Thermo Electron Corporation, to sell the Registrant's
             Thermo Trilogy Corporation subsidiary, which has been classified as
             discontinued operations. This amended information replaces the
             corresponding information filed originally in the Exhibit 13 to
             Form 10-K.

<PAGE>
                                                                    FORM 10-K/A

                            THERMO ECOTEK CORPORATION

                                   SIGNATURES

      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. 1 on
Form 10-K/A to be signed on its behalf by the undersigned, thereunto duly
authorized.

Date:  May 4, 2000

                                   THERMO ECOTEK CORPORATION



                                   By:  /s/ Theo Melas-Kyriazi
                                   Theo Melas-Kyriazi
                                   Vice President and Chief Financial Officer
                                   (Principal Financial and Accounting Officer)