As filed with the Securities and Exchange Commission on March 2, 2006.
                           Registration No. 333-46408
            --------------------------------------------------------

                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549
                                 ---------------

                         POST-EFFECTIVE AMENDMENT NO. 1
                                       ON
                                    FORM S-8
                          Registration Statement Under
                           The Securities Act of 1933
                                 ---------------

                           THERMO ELECTRON CORPORATION
             (Exact name of registrant as specified in its charter)
                                 ---------------



                                                       

        DELAWARE                                                04-2209186
(State or other jurisdiction of                              (I.R.S. Employer
incorporation or organization)                            Identification Number)



                                 81 Wyman Street
                        Waltham, Massachusetts 02454-9046
               (Address of Principal Executive Offices) (Zip Code)

                THERMO TERRATECH INC. DIRECTORS STOCK OPTION PLAN
        THERMO ELECTRON CORPORATION - THERMO TERRATECH INC. NONQUALIFIED
                            STOCK OPTION PLAN (1996)
         THERMO ELECTRON CORPORATION DIRECTORS STOCK OPTION PLAN (THERMO
                               TERRATECH SHARES)
           THERMO TERRATECH INC. DIRECTORS DEFERRED COMPENSATION PLAN
              THERMO TERRATECH INC. NONQUALIFIED STOCK OPTION PLAN
        THERMO ELECTRON CORPORATION - THERMO TERRATECH INC. NONQUALIFIED
                            STOCK OPTION PLAN (1986)
                   THERMO TERRATECH INC. EQUITY INCENTIVE PLAN
          THERMO INSTRUMENT SYSTEMS INC. EMPLOYEES' STOCK PURCHASE PLAN
                            (Full Title of the Plan)

                          Seth H. Hoogasian, Secretary
                           Thermo Electron Corporation
                                 81 Wyman Street
                        Waltham, Massachusetts 02454-9046

                                 (781) 622-1000
          (Telephone Number, Including Area Code, of Agent For Service)




                          Deregistration of Securities

     This  Post-Effective  Amendment  No.  1 on  Form  S-8 to  the  Registration
Statement  on Form  S-8  (Registration  No.  333-46408)  is  being  filed by the
Registrant to remove from  registration any of the securities that remain unsold
thereunder  as of the  date of  filing  of this  post-effective  amendment.  The
securities were previously  registered for sale under the Thermo  Terratech Inc.
Directors Stock Option Plan, the Thermo Electron  Corporation - Thermo Terratech
Inc.  Nonqualified  Stock Option Plan (1996),  the Thermo  Electron  Corporation
Directors Stock Option Plan (Thermo Terratech shares), the Thermo Terratech Inc.
Directors  Deferred  Compensation  Plan, the Thermo Terratech Inc.  Nonqualified
Stock Option Plan,  the Thermo  Electron  Corporation  - Thermo  Terratech  Inc.
Nonqualified  Stock  Option  Plan  (1986),  the  Thermo  Terratech  Inc.  Equity
Incentive Plan, and the Thermo Instrument Systems Inc. Employees' Stock Purchase
Plan (collectively,  the "Plans"). The deregistered  securities represent shares
subject to  options  granted  under the Plans that  expired,  were  canceled  or
terminated without having been exercised or shares that were available under the
Plans which  remain  unsold as of the date of the filing of this  post-effective
amendment.   As  such,  the  Registrant  hereby  removes  such  securities  from
registration and the registration is hereby terminated.




                                   SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, Thermo Electron
certifies  that it has  reasonable  grounds to believe  that it meets all of the
requirements  for  filing on Form S-8 and has duly  caused  this  Post-Effective
Amendment on Form S-8 to be signed on its behalf by the  undersigned,  thereunto
duly authorized, in the City of Waltham, Commonwealth of Massachusetts,  on this
28th day of February, 2006.

                                    THERMO ELECTRON CORPORATION


                                    By:    /s/ Marijn E. Dekkers
                                           -------------------------------------
                                           Marijn E. Dekkers
                                    Its:   President and Chief Executive Officer

     Pursuant  to  the   requirements  of  the  Securities  Act  of  1933,  this
Post-Effective Amendment on Form S-8 has been signed by the following persons in
the capacities and on the dates indicated.



                                                                                                          

               Signature                                                  Title                                       Date
               ---------                                                  -----                                       ----
                                                            President, Chief Executive
/s/ Marijn E. Dekkers                                       Officer and Director (Principal
------------------------------------------------------      Executive Officer)                                  February 28, 2006
Marijn E. Dekkers

/s/ Jim P. Manzi                                            Chairman of the Board and
------------------------------------------------------      Director                                            February 28, 2006
Jim P. Manzi
                                                            Vice President and Chief
/s/ Peter M. Wilver                                         Financial Officer (Principal
------------------------------------------------------      Financial Officer)                                  February 28, 2006
Peter M. Wilver
                                                            Corporate Controller and Chief
/s/ Peter E. Hornstra                                       Accounting Officer (Principal
------------------------------------------------------      Accounting Officer)                                 February 28, 2006
Peter E. Hornstra

/s/ John L. LaMattina
------------------------------------------------------      Director                                            February 28, 2006
John L. LaMattina

/s/ Peter J. Manning
------------------------------------------------------      Director                                            February 28, 2006
Peter J. Manning

/s/ Robert A. McCabe
------------------------------------------------------      Director                                            February 28, 2006
Robert A. McCabe

/s/ Robert W. O'Leary
------------------------------------------------------      Director                                            February 28, 2006
Robert W. O'Leary




/s/ Michael E. Porter
------------------------------------------------------      Director                                            February 28, 2006
Michael E. Porter

/s/ Elaine S. Ullian
------------------------------------------------------      Director                                            February 28, 2006
Elaine S. Ullian