IMAX CORPORATION

                                  EXHIBIT 10.21

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                            THIRD AMENDING AGREEMENT

This Amendment to Employment Agreement dated as of February 14, 2006 (the
"Amending Agreement") is made between:

IMAX CORPORATION, a corporation incorporated under the laws of Canada
(hereinafter referred to as the "Company"),

and

ROBERT D. LISTER (the "Executive")

WHEREAS, the Company wishes to enter into this Amending Agreement to amend and
extend the Employment Agreement dated as of May 17, 1999 between Imax Ltd, the
Company and Executive, as modified and amended by those Amending Agreements
dated as of April 4, 2001 and January 1, 2004, (together, the "Agreement"),
whereunder the Executive provides services to the Company, and the Executive
wishes to so continue such engagement, as hereinafter set forth;

AND WHEREAS, on January 1, 2001 Imax Ltd. assigned all of its rights and
obligations pursuant to the Agreement to the Company, and the Executive has
consented to such assignment;

NOW, THEREFORE, in consideration of good and valuable consideration, the receipt
and sufficiency of which is hereby acknowledged, the parties hereto agree as
follows:

1. Section 1.3 of the Agreement shall be deleted and replaced with the
following:

"Section 1.3 Term of Employment. The Employee's employment under this Agreement
commenced on the 17th day of May, 1999 (the "Commencement Date") and shall
terminate on the earlier of (i) January 1, 2008, or (ii) the termination of the
Employee's employment pursuant to this Agreement. The period commencing as of
the Commencement Date and ending on January 1, 2008 or such later date to which
the term of the Employee's employment under this Agreement shall have been
extended is hereinafter referred to as the "Employment Term."

2. Section 2.1 of the Agreement shall be deleted and replaced with the
following:

"Section 2.1 Base Salary. Effective January 1, 2006, the Executive's Base Salary
shall be US$ 365,700. Effective January 1, 2007, the Executive's Base Salary
shall be US$ 402,270."

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3. Section 6 of the Agreement shall be deleted and replaced with the following:

Subject to Section 7.1 and 7.2, the Executive shall be required to mitigate the
amount of any payment provided for in Section 4.1.1 (other than the Termination
Payment) by seeking other employment or remunerative activity reasonably
comparable to his duties hereunder, and, upon Executive's obtaining such other
employment or remunerative activity any payment to be made by the Company under
Section 4.1.1 (other than the Termination Payment) will be reduced by a total of
one-quarter (1/4) of the amount of such payment prior to the Executive's
obtaining new employment or remunerative activity. Notwithstanding anything
herein to the contrary, in the event that there is either (a) a change in
control of the Company i.e. any person, or group of persons acting in concert,
other than Bradley J. Wechsler and Richard L. Gelfond, acquiring greater than
fifty percent (50%) of the outstanding common shares of the Company, whether by
direct or indirect acquisition or as a result of a merger or reorganization; or
(b) a significant change in the Executive's reporting relationship (either, a
"Non-Mitigation Event"), then, if at any time subsequent to the occurrence of
such Non-Mitigation Event the Executive is terminated from the Company Without
Cause, (i) Executive shall have no obligation to mitigate the amounts provided
in Section 4.1.1, and (ii) the Severance Period (as defined in Section 4.1.1)
shall be a minimum of eighteen (18) months in duration. For clarity, a
termination of Executive's employment Without Cause shall include, but not be
limited to, the events cited in Section 2.3(b)(iii) and (iv), and a termination
by virtue of the expiry of the Agreement.

4. The parties confirm that the August 21, 2000 letter agreement with regard to
Executive's incentive payments and benefits remains in full force and effect and
Executive shall be entitled to US$ 107,500 thereunder from the Company upon a
termination Without Cause within two (2) years of the completion of a
Transaction (as defined therein).

5. Effective as soon as is practicable after the date hereof, the Executive
shall be granted non-qualified options (the "Options") to purchase 50,000 shares
of common stock of the Company (the "Common Shares"), at an exercise price per
Common Share equal to the Fair Market Value, as defined in the Company's Stock
Option Plan. The Options shall vest as to 10% on the first anniversary of the
grant date, 15% on the second anniversary of the grant date, 20% on the third
anniversary of the grant date, 25% on the fourth anniversary of the grant date
and 30% on the fifth anniversary of the grant date, and shall otherwise be
treated in accordance with the terms of Section 2.3 of the Agreement.

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Except as amended herein, all other terms of the Agreement shall remain in full
force, unamended.

IN WITNESS WHEREOF, the Company and the Executive have duly executed and
delivered this Amending Agreement on this 14(th) day of February, 2006.



                                           IMAX  CORPORATION


                                           By:       "Richard L. Gelfond"
                                               ---------------------------------
                                               Name:  Richard L. Gelfond
                                               Title: Co-Chief Executive Officer



                                           By:      "Bradley J. Wechsler"
                                               ---------------------------------
                                               Name:  Bradley J. Wechsler
                                               Title: Co-Chief Executive Officer






SIGNED, SEALED AND DELIVERED               EXECUTIVE:
in the presence of:



    "Stephen G. Abraham"                     "Robert D. Lister"
- ----------------------------               -------------------------------------
Witness  Stephen G. Abraham                Robert D. Lister

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