================================================================================

                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                   ----------

                                    FORM 8-K

                                   ----------

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

        Date of Report (Date of earliest event reported): April 20, 2005

                                GSI LUMONICS INC.
             ------------------------------------------------------
             (Exact name of registrant as specified in its charter)

                              New Brunswick, Canada
                 ----------------------------------------------
                 (State or other jurisdiction of incorporation)

           000-25705                                 98-0110412
    ------------------------            ------------------------------------
    (Commission File Number)            (I.R.S. Employer Identification No.)

                 39 Manning Road, Billerica, Massachusetts 01821
          ------------------------------------------------------------
          (Address of principal executive offices, including zip code)

                                 (978) 439-5511
              ----------------------------------------------------
              (Registrant's telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to
simultaneously satisfy the filing obligation of the registrant under any of the
following provisions (see General Instruction A.2. below):

[ ]  Written communications pursuant to Rule 425 under the Securities
     Act (17 CFR 220.425)

[ ]  Soliciting material pursuant to Rule 14a-12 under the Exchange
     Act (17 CFR 240.14a-12)

[ ]  Pre-commencement communications pursuant to Rule 14d-2(b) under the
     Exchange Act (17 CFR 240.14d-2(b))

[ ]  Pre-commencement communications pursuant to Rule 13e-4(c) under the
     Exchange Act (17 CFR 240.13e-4(c))

================================================================================



ITEM 2.02.  RESULTS OF OPERATIONS AND FINANCIAL CONDITION.

     On April 20, 2005, GSI Lumonics Inc. (the "Company") issued a press release
announcing its estimated expectations for revenue and net income for its first
quarter of 2005. A copy of the press release is attached as Exhibit 99.1 to this
Current Report on Form 8-K and incorporated herein by reference.

ITEM 9.01.  FINANCIAL STATEMENTS AND EXHIBITS.

     (a)    Financial Statements of Businesses Acquired.

            Not applicable.

     (b)    Pro Forma Financial Information.

            Not applicable.

     (c)    Exhibits.

            99.1      Press Release issued April 20, 2005

     The information in this Current Report on Form 8-K (including the press
release attached as Exhibit 99.1 hereto) shall not be deemed "filed" for
purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the
"Exchange Act") or otherwise subject to the liabilities of that section, nor
shall it be deemed incorporated by reference into any filing under the
Securities Act of 1933, as amended, or the Exchange Act, regardless of any
general incorporation language in such filing, unless the Company expressly sets
forth in such future filing that such information is to be considered "filed" or
incorporated by reference therein.



                                    SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended,
the Registrant has duly caused this report to be signed on its behalf by the
undersigned hereunto duly authorized.

                                              GSI LUMONICS INC.
                                              (Registrant)

Date:  April 20, 2005                         By:  /s/ Thomas R. Swain
                                                   -----------------------------
                                                   Thomas R. Swain
                                                   Vice President, Finance and
                                                   Chief Financial Officer



                                  EXHIBIT INDEX

Exhibit No.      Description
-----------      ------------------------------------
  99.1           Press Release issued April 20, 2005.