METHANEX CORPORATION STOCK OPTION PLAN 2006

                                                                    EXHIBIT 4.3
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                              METHANEX CORPORATION

                             STOCK OPTION PLAN 2006


A.       THE PLAN

        The Stock   Option Plan 2006 (the   "Plan") is the   amended and   restated
stock   option   plan   of   Methanex    Corporation    ("Corporation"),    reflecting
amendments to and including   March 3, 2006, of the prior Incentive Stock Option
Plan.   The Plan for key   employees   and   directors of the   Corporation   and its
majority-owned subsidiaries ("subsidiaries") to purchase unissued common shares
("Shares") of the Corporation is hereby established on the terms and conditions
hereinafter set out.

B.       PURPOSE

        The purpose of the Plan is to develop the interest of key employees and
directors of the Corporation and its   subsidiaries in growth and development by
providing   them with the   opportunity   through   options on Shares to acquire an
increased financial interest in the Corporation.

C.       GRANT OF OPTIONS

        The Board of Directors of the   Corporation may from time to time in its
discretion grant to officers,   directors and other employees of the Corporation
and its subsidiaries (who in each case must be full-time employees or directors
of the   Corporation   or a   subsidiary   and who,   in the opinion of the Board of
Directors,   are key   employees or   directors),   an option to acquire all or any
part of an   allotment   of Shares of the   Corporation   upon and   subject to such
terms,   conditions and limitations as are herein contained and otherwise as the
Board of Directors may from time to time determine with respect to each option.

        The   maximum   number of Shares that may be issued from and after May 2,
2006   pursuant   to options   granted   pursuant   to this Plan is   5,250,000.   The
maximum   number of Shares   which may be reserved for issuance to, or covered by
any   option   granted   to,   any   person   shall not exceed the lower of 5% of the
outstanding issue or the maximum number permitted by the applicable   securities
laws and   regulations   of   Canada   or of the   United   States   or any   political
subdivision   of either,   and the by-laws,   rules and   regulations   of any stock
exchange or other trading   facility upon which the Shares are listed or traded,
as the case may be.

D.       EXERCISE PRICE

        The price of the Shares, upon exercise of each option granted under the
Plan,   shall be a price   fixed for such option by the Board of   Directors,   but
such price   shall be not less than the fair   market   value of the Shares on the
date the option is granted.   The fair market   value for this   purpose   shall be
deemed to be the US Dollar   equivalent of the closing price at which board lots
of the   Corporation's   Shares were traded on the Toronto Stock   Exchange on the
day   preceding   the date on which the option is granted or if no board lots are
traded on such day then the US Dollar   equivalent of the closing price at which
board lots were traded on the most recent day upon which at least one board lot
was traded on such   Exchange.   The "US Dollar   equivalent of the closing price"
shall be   determined   using the US   Dollar/Canadian   Dollar   Daily Noon Rate as
published   by the Bank of   Canada   on the same   day that the   closing   price is
established.

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E.       TERM

        The Shares   identified   in the option may be   purchased at such time or
times   after   the   option   is   granted   as may be   determined   b