UNITED STATES

                       SECURITIES AND EXCHANGE COMMISSION

                              WASHINGTON, DC 20549
              ----------------------------------------------------

                                    FORM 11-K


(mark one)

[X]  Annual Report Pursuant to Section 15(d) of the Securities Exchange Act of
     1934 for the Fiscal Year Ended December 31, 2003

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

                          Commission File Number 1-8002

                     THERMO ELECTRON CORPORATION CHOICE PLAN

     A.   Full title of the plan and address of the plan, if different from that
          of the issuer named below:

          Thermo Electron Corporation Choice Plan

     B.   Name of issuer of the securities held pursuant to the plan and the
          address of the principal executive office:

          Thermo Electron Corporation
          81 Wyman Street
          P.O. Box 9046 Waltham, Massachusetts 02454-9046



Thermo Electron Corporation Choice Plan
December 31, 2003 and 2002
--------------------------------------------------------------------------------

     Pursuant to the  requirements  of the Securities  Exchange Act of 1934, the
trustees (or other persons who administer  the employee  benefit plan) have duly
caused  this  annual  report  to be  signed  by the  undersigned  hereunto  duly
authorized.

              THERMO ELECTRON CORPORATION CHOICE PLAN

              By:   Thermo Electron Corporation, Pension Committee


              By:   /s/ Theo Melas-Kyriazi
                    -----------------------------------------------
                    Theo Melas-Kyriazi
                    Chief Financial Officer and Member of the Plan Administrator

Date:  June 25, 2004







Thermo Electron Corporation Choice Plan
Financial Statements and Supplementary Information
December 31, 2003 and 2002







                                                                                                                   

Thermo Electron Corporation Choice Plan
Index
December 31, 2003 and 2002
---------------------------------------------------------------------------------------------------------------------------------

                                                                                                                       Page(s)

Report of Independent Registered Public Accounting Firm............................................................      1

Financial Statements

Statements of Net Assets Available for Benefits.....................................................................     2

Statement of Changes in Net Assets Available for Benefits...........................................................     3

Notes to Financial Statements.......................................................................................   4-7

Supplementary Schedule*

Schedule H, line 4i - Schedule of Assets Held (at End of Year)......................................................     8


* Other  supplemental  schedules  required  by  Section  2520-103.10  of  the Department of Labor's Rules and
  Regulations  for Reporting and  Disclosure under the Employee Retirement Income Security Act of 1974 have
  been omitted because they are not applicable.







Thermo Electron Corporation Choice Plan
Report of Independent Registered Public Accounting Firm
--------------------------------------------------------------------------------

To the Participants, Administrator and Pension Committee of
Thermo Electron Corporation Choice Plan


In our opinion, the accompanying statements of net assets available for benefits
and the related statement of changes in net assets available for benefits
present fairly, in all material respects, the net assets available for benefits
of Thermo Electron Corporation Choice Plan (the "Plan") at December 31, 2003 and
2002, and the changes in net assets available for benefits for the year ended
December 31, 2003 in conformity with accounting principles generally accepted in
the United States of America. These financial statements are the responsibility
of the Plan's management. Our responsibility is to express an opinion on these
financial statements based on our audits. We conducted our audits of these
statements in accordance with the standards of the Public Company Accounting
Oversight Board (United States) and auditing standards generally accepted in the
United States of America. Those standards require that we plan and perform the
audit to obtain reasonable assurance about whether the financial statements are
free of material misstatement. An audit includes examining, on a test basis,
evidence supporting the amounts and disclosures in the financial statements,
assessing the accounting principles used and significant estimates made by
management, and evaluating the overall financial statement presentation. We
believe that our audits provide a reasonable basis for our opinion.

Our audits were conducted for the purpose of forming an opinion on the basic
financial statements taken as a whole. The supplemental schedule H, line 4i -
schedule of assets held (at end of year) is presented for the purpose of
additional analysis and is not a required part of the basic financial statements
but is supplementary information required by the Department of Labor's Rules and
Regulations for Reporting and Disclosure under the Employee Retirement Income
Security Act of 1974. This supplemental schedule is the responsibility of the
Plan's management. The supplemental schedule has been subjected to the auditing
procedures applied in the audit of the basic financial statements and, in our
opinion, is fairly stated in all material respects in relation to the basic
financial statements taken as a whole.


PricewaterhouseCoopers LLP

Boston, Massachusetts
June 18, 2004


                                       1




                                                                                                             

Thermo Electron Corporation Choice Plan
Statements of Net Assets Available for Benefits
December 31, 2003 and 2002
---------------------------------------------------------------------------------------------------------------------------------



                                                                                                        2003              2002
                                                                                                 --------------    --------------

Assets
Investments, at fair value                                                                       $  427,399,405    $  345,632,550
Loans to participants                                                                                 5,636,340         5,976,961
                                                                                                 --------------    --------------

                                                                                                    433,035,745       351,609,511
                                                                                                 --------------    --------------
Receivables
 Employer contributions                                                                                 712,594           546,587
 Participant contributions                                                                            1,442,413         1,082,122
 Other                                                                                                      548             5,616
                                                                                                 --------------    --------------

                                                                                                      2,155,555         1,634,325
                                                                                                 --------------    --------------
    Net assets available for benefits                                                            $  435,191,300    $  353,243,836
                                                                                                 ==============    ==============






                 See accompanying notes to financial statements.
                                       2





                                                                                                                
Thermo Electron Corporation Choice Plan
Statement of Changes in Net Assets Available for Benefits
For the Year Ended December 31, 2003
---------------------------------------------------------------------------------------------------------------------------------

Addition to net assets attributed to investment income
 Interest and dividends                                                                                            $    8,423,928
 Net appreciation in fair value of investments                                                                         72,025,833
                                                                                                                   --------------

    Total investment income                                                                                            80,449,761
                                                                                                                   --------------

Contributions
 Employer                                                                                                              11,703,913
 Participant                                                                                                           24,510,500
                                                                                                                   --------------

    Total contributions                                                                                                36,214,413
                                                                                                                   --------------

Deductions from net assets attributed to
 Benefits paid to participants                                                                                         34,686,849
 Administrative expenses                                                                                                   29,861
                                                                                                                   --------------

    Total deductions                                                                                                   34,716,710

Net increase in net assets available for benefits                                                                      81,947,464

Net assets available for benefits
 Beginning of year                                                                                                    353,243,836
                                                                                                                   --------------

 End of year                                                                                                       $  435,191,300
                                                                                                                   ==============






                 See accompanying notes to financial statements.

                                        3




Thermo Electron Corporation Choice Plan
Notes to Financial Statements
December 31, 2003 and 2002
--------------------------------------------------------------------------------

1.       Plan Description

        The following description of the Thermo Electron Corporation Choice Plan
        (the Plan) provides only general information. Participants should refer
        to the Plan agreement for a more complete description of the Plan's
        provisions.

        General
        The Plan is a defined contribution plan. The Plan covers eligible
        full-time and part-time employees of Thermo Electron Corporation and
        subsidiaries (the Company) who have completed two months of service. The
        Plan is subject to the provisions of the Employee Retirement Income
        Security Act of 1974 (ERISA).

        On May 31, 2002, the Thermo Neslab, Inc. 401(k) Plan was merged into the
        Plan. The balance of $14,627,249 for the net assets available for
        benefits as of May 31, 2002 was transferred into the Plan.

        On July 31, 2002, the Thermo Finnigan LLC 401(k) Plan was merged into
        the Plan. The balance of $47,453,179 for the net assets available for
        benefits as of July 31, 2002 was transferred into the Plan.

        As of December 31, 2002, the participant accounts and the net assets of
        the Spectra-Physics 401(k) Plan were transferred into the Plan, totaling
        $36,004,050. The financial statements reflect the merger as if it
        occurred at the close of business December 31, 2002. The participants of
        Spectra-Physics of the 401(k) plan were allowed to contribute effective
        January 1, 2003.

        Contributions
        Each year participants may contribute up to 50% of pre-tax annual
        compensation or $12,000, as defined in the Plan. Participants may also
        contribute amounts representing distributions from other qualified
        defined benefit or defined contribution plans. Beginning on the first
        day of the calendar month following completion of one year of service,
        the Company makes non-discretionary matching contributions equal to 200%
        of the first 2% and 25% of the next 2% of base compensation that a
        participant contributes to the Plan. Participants direct the investment
        of their contributions and the Company match into various investment
        options offered by the Plan. The Plan currently offers the Company's
        common stock fund and sixteen investment funds as investment options for
        participants. Contributions are subject to certain limitations.

        Participant Accounts
        Each participant's account is credited with the participant's
        contributions and allocations of the Company's contribution and plan
        earnings, and charged with an allocation of administrative expenses, if
        any. Allocations are based on participant earnings or account balances,
        as defined. The benefit to which a participant is entitled is the
        benefit that can be provided from the participant's vested account.

        Vesting
        Participants are immediately vested in their voluntary contributions
        plus actual earnings thereon. Vesting in the Company matching
        contributions plus actual earnings thereon is based on years of service.
        A participant is 100% vested after three years of credited service.

        A participant is automatically 100% vested in all contributions upon the
        attainment of age 65, upon becoming permanently disabled, or upon death
        while still an active participant.

                                       4

Thermo Electron Corporation Choice Plan
Notes to Financial Statements
December 31, 2003 and 2002
--------------------------------------------------------------------------------

        Participant Loans
        Participants may only borrow from their employee portion of fund
        accounts a minimum of $1,000 up to a maximum equal to $50,000 or 50% of
        the vested account balance, whichever is less. The term of the loan is
        generally five years except when use of the proceeds is for the purchase
        of a primary residence, for which the term can be up to 30 years. The
        loans are secured by the balance in the participant's account and bear
        interest at a rate commensurate with local prevailing rates as
        determined by the plan administrator. The interest rates on plan loans
        range from 5% to 11% at December 31, 2003. Principal and interest are
        repaid through payroll deductions.

        Benefit Payments and Plan Withdrawals
        On termination of service due to death, disability or retirement, a
        participant (or beneficiary) may elect to receive either a lump-sum
        amount equal to the value of the participant's vested interest in his or
        her account or periodic installments. For termination of service due to
        other reasons, a participant may receive the value of the vested
        interest in his or her account as a lump-sum distribution. Withdrawals
        may be made under certain other circumstances in accordance with the
        Plan document.

        Forfeitures
        Upon a participant's break in service, as defined, the nonvested portion
        of the participant's account is forfeited and is used to reduce the
        Company's future funding requirements. If a participant who has
        terminated employment is rehired by the Company before the greater of a
        five-year break in service or the number of the participant's years of
        service prior to the participant's break in service, the participant
        shall be reinstated in such forfeited amount. In 2003, Company
        contributions were reduced by $205,477 from forfeited nonvested
        accounts.

        Transfer In/Out
        In connection with certain reorganization activities at the Company, the
        assets of certain other plans sponsored by subsidiaries of the Company
        have been transferred into the Plan in connection with the merger of
        those plans. Additionally, the reorganization has involved a number of
        business dispositions. As a result, the plan assets in the accounts of
        the affected employees have sometimes been transferred to plans
        sponsored by the acquirers of these businesses disposed.

2.      Summary of Significant Accounting Policies

        Use of Estimates
        The Plan's financial statements are prepared on the accrual basis of
        accounting. The preparation of the financial statements in conformity
        with accounting principles generally accepted in the United States of
        America requires management to make estimates and assumptions that
        affect the reported amounts of assets and liabilities and changes
        therein. Actual results could differ from those estimates. Certain prior
        year balances have been reclassified to conform with the current year
        financial statement presentation.

        Investment Valuation
        Investments are stated at fair value as determined by Fidelity
        Management Trust Company, a trust company that is the trustee and
        custodian of the Plan's investment assets. Common shares are valued
        based on quoted market prices. Registered investment companies and bank
        collective investment funds are valued based on net asset value.
        Participant loans are valued at cost plus accrued interest, which
        approximates fair value.

        Payment of Benefits
        Benefits are recorded when paid.

                                       5

Thermo Electron Corporation Choice Plan
Notes to Financial Statements
December 31, 2003 and 2002
--------------------------------------------------------------------------------

        Risks and Uncertainties
        The Plan invests in a combination of investment securities which are
        exposed to various risks, such as interest rate, market and credit. Due
        to the level of risk associated with certain investment securities and
        the level of uncertainty related to changes in the value of investment
        securities, it is at least reasonably possible that changes in risks in
        the near term would materially affect participants' account balances and
        the amounts reported in the statement of net assets available for
        benefits and the statement of changes in net assets available for
        benefits.

3.      Tax Status

        The Plan has received a favorable determination letter dated September
        18, 2003 from the Internal Revenue Service. The Plan has been amended
        since receiving the determination letter; however, the Plan
        administrator, management and the Plan's tax counsel believe that the
        Plan has been designed and operated in compliance with the applicable
        requirements of the Internal Revenue Code.

4.      Investments

        Investments that represent five percent or more of the Plan's net assets
are as follows:


                                                                                                              

                                                                                                              December 31,
                                                                                                  -------------------------------
                                                                                                         2003             2002
                                                                                                  -------------     -------------

        Dodge and Cox Stock Fund                                                                  $  68,531,423     $           -
        Managed Income Portfolio II: Class II                                                        80,699,253        82,028,407
        Fidelity Equity-Income II Fund                                                                        -        46,954,580
        Fidelity Blue Chip Growth Fund                                                               53,078,631        43,974,327
        Fidelity Balanced Fund                                                                       53,083,335        42,617,193
        Fidelity Magellan Fund                                                                       30,880,451        24,014,123
        Fidelity Growth Company Fund                                                                 31,880,444        20,369,301
        Fidelity Diversified International Fund                                                      25,597,955                 -
        U.S. Equity Index Commingled Pool                                                            23,610,546        18,548,584
        PIMCO Total Return Fund: Class ADM                                                                    -        17,699,913


        Purchases and sales of investments are recorded on a trade-date basis.
        Interest income is recorded on the accrual basis. Dividends are recorded
        on ex-dividend date.

5.      Related Party Transactions

        Certain Plan investments are managed by the Fidelity Management Trust
        Company, which is a trustee as defined by the Plan. Therefore, these
        transactions qualify as party-in-interest transactions. There were no
        fees paid by the Plan for investment management services for the period
        ended December 31, 2003. These transactions, as well as participant
        loans, qualify as party in interest transactions.

        The Plan invests in a unitized stock fund, Thermo Electron Stock Fund
        (the Fund), which is comprised of a short-term investment fund component
        and shares of common stock of the Company. The unit values of the Fund
        are recorded and maintained by the trustee. During the year ended
        December 31, 2003, the Plan purchased units of the Fund in the
        approximate amount of $960,367, sold units of the Fund in the
        approximate amount of $2,033,948, and had net appreciation and dividends
        on the Fund in the approximate amount of $2,731,447. The total value of
        the Plan's interest in the Fund was approximately $14,081,420 and
        $12,423,554 at December 31, 2003 and 2002, respectively.

                                       6

Thermo Electron Corporation Choice Plan
Notes to Financial Statements
December 31, 2003 and 2002
--------------------------------------------------------------------------------

6.      Plan Termination

        Although it has not expressed an intent to do so, the Company has the
        right under the Plan to discontinue its contributions at any time and to
        terminate the Plan subject to the provisions of ERISA. In the event of
        Plan termination, participants would become 100% vested in their
        employer contributions.

7.       Administrative Expenses

        The Company and the Plan pay for administrative expenses associated with
        management of and professional services for the Plan. Administrative
        fees for hardship withdrawals and loan transactions are paid by the
        participants. The administrative expenses included in the statement of
        changes in net assets available for benefits represent expenses paid by
        the participants. During the year, the Plan received a settlement of
        approximately $147,000 from the prior recordkeeper. The proceeds from
        the settlement were utilized to offset administrative expenses.

8.       Subsequent Event

        The Company recently announced that it has entered into a definitive
        agreement for the sale of its optical technologies segment,
        Spectra-Physics, to Newport Corporation. As a result of this
        disposition, the active participation in the Plan of employees in this
        segment will cease as of the sale date.


                                       7




                                                                                                                 

Thermo Electron Corporation Choice Plan
Schedule H, Line 4i
Schedule of Assets Held (at End of Year)
December 31, 2003                                                                                           Supplemental Schedule
---------------------------------------------------------------------------------------------------------------------------------
Description of Investments                                                                   Units/Shares           Current Value

Mutual Funds
 Dodge and Cox Stock Fund                                                                         602,315         $    68,531,423
 Fidelity Balanced Fund (1)                                                                     3,169,154              53,083,335
 Fidelity Blue Chip Growth Fund (1)                                                             1,339,355              53,078,631
 Fidelity Diversified International Fund (1)                                                    1,061,275              25,597,955
 Fidelity Growth Company Fund (1)                                                                 636,717              31,880,444
 Fidelity Magellan Fund (1)                                                                       315,945              30,880,451
 Freedom 2000 Fund (1)                                                                             52,957                 623,829
 Freedom 2010 Fund (1)                                                                            122,622               1,596,544
 Freedom 2020 Fund (1)                                                                            247,734               3,225,503
 Freedom 2030 Fund (1)                                                                            169,773               2,198,563
 Freedom 2040 Fund (1)                                                                             67,289                 508,701
 Freedom Income Fund (1)                                                                           73,671                 817,014
 PIMCO Total Return Fund: Class ADM                                                             1,781,095              19,075,530
 T. Rowe Price Small-Cap Stock Fund, Inc.                                                         640,109              17,910,263

Fidelity Group Trust for Employee Benefit Plans
 Managed Income Portfolio II: Class II (1)                                                     80,699,253              80,699,253
 U.S. Equity Index Commingled Pool (1)                                                            699,157              23,610,546
 Thermo Electron Stock Fund (1)                                                                   898,069              14,081,420
 Loans to participants (for a term not exceeding 30 years at interest rates ranging
  from 5% to 11%) (1)                                                                                                   5,636,340
                                                                                                                  ---------------

                                                                                                                  $   433,035,745
                                                                                                                  ===============



(1) All investments are a party in interest to the Plan.

                                       8





       

Thermo Electron Corporation Choice Plan
Exhibit Index
December 31, 2003 and 2002
---------------------------------------------------------------------------------------------------------------------------------
Exhibit
Number    Description of Exhibit
---------------------------------------------------------------------------------------------------------------------------------

23.1      Consent of PricewaterhouseCoopers LLP.

32.1      Certification of the Vice President of Human Resources Pursuant to 18 U.S.C. Section 1350.

32.2      Certification of the Chief Financial Officer Pursuant to 18 U.S.C. Section 1350.




                                       9