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                                                                 EXHIBIT 10.4(b)


                   FIRST AMENDMENT TO AMERISTAR CASINOS, INC.
                            1999 STOCK INCENTIVE PLAN

     THIS FIRST AMENDMENT TO AMERISTAR CASINOS, INC. 1999 STOCK INCENTIVE PLAN
("Amendment") is made as of this 8th day of December, 2000.

     WHEREAS, at the meeting of the Board of Directors of Ameristar Casinos,
Inc. (the "Company") on December 8, 2000, the Board determined that it was in
the Company's best interests to amend the Company's 1999 Stock Incentive Plan
(the "Plan") to increase the number of shares of the Company's common stock
("Shares") that may be distributed under the Plan and to increase the number of
Shares that may be distributed to any one person in any calendar year under the
Plan.

     WHEREAS, pursuant to the authority granted by the Board, the Company has
decided to amend the Plan in accordance with the terms and conditions set forth
below.

                                   AMENDMENTS

1. TOTAL SHARES FOR DISTRIBUTION. The existing paragraph 4.1 of the Plan is
deleted, and the following is inserted as the new paragraph 4.1:

     The total number of shares of Stock reserved and available for distribution
     under the Plan shall be 4,600,000 (subject to adjustment as provided in
     Section 4.3); provided, however, that no award of a Stock Option or
     Restricted Stock may be made at any time if, after giving effect to such
     award, (i) the total number of shares of Stock issued upon the exercise of
     options under the Plan and the Company's Management Stock Option Incentive
     Plan, as amended and restated through September 4, 1996 (the "Prior Plan")
     plus (ii) the total number of shares of Stock issuable upon exercise of all
     outstanding options of the Company under the Plan and the Prior Plan plus
     (iii) the total number of shares of Stock underlying awards of Restricted
     Stock under the Plan (whether or not the applicable restrictions have
     lapsed) would exceed 4,600,000 shares (subject to adjustment as provided in
     Section 4.3). Shares of Stock issuable in connection with any award under
     the Plan may consist of authorized but unissued shares or treasury shares.

2. CALENDAR YEAR LIMIT. The existing clause (c) of paragraph 3.2 of the Plan is
deleted, and the following is inserted as the new clause (c) of paragraph 3.2.

     (c) to determine the number of shares of the common stock of the Company,
     $0.01 par value (the "Stock"), to be covered by each award granted
     hereunder, provided that no Participant will be granted Stock Options on or
     with respect to more than 1,000,000 shares of Stock in any calendar year.

3. GENERAL. Except as modified in this Amendment, the Plan remains in full force
and effect. The headings used in this Amendment are for convenience purposes
only and should not be read to limit or alter provisions of this Amendment.


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     IN WITNESS WHEREOF, Ameristar Casinos, Inc. has executed this Amendment as
of the date set forth above.


AMERISTAR CASINOS, INC.,
a Nevada corporation


By: /s/ THOMAS M. STEINBAUER
   ------------------------------------------------------
        Thomas M. Steinbauer
        Senior Vice President and Chief Financial Officer






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