As filed with the Securities and Exchange Commission on March 2, 2006.
                            Registration No. 33-51187
            --------------------------------------------------------

                       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 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.  33-51187)  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  Instrument
Systems Inc.  Employees'  Stock  Purchase  Plan (the "Plan").  The  deregistered
securities  represent  shares that were  available  under the Plan 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