EXHIBIT 4.1

CONFORMED AS EXECUTED

FOURTH AMENDMENT TO CREDIT AGREEMENT

          FOURTH AMENDMENT TO CREDIT AGREEMENT (this “Amendment”), dated as of November 10, 2010 among AMERISTAR CASINOS, INC., a Nevada corporation (the “Borrower”), the various lenders party to the Credit Agreement referred to below (the “Lenders”) and DEUTSCHE BANK TRUST COMPANY AMERICAS, as Administrative Agent (all capitalized terms used herein and not otherwise defined herein shall have the respective meanings given to such terms in the Credit Agreement as defined below).

W I T N E S S E T H:

          WHEREAS, the Borrower, the Lenders, the Administrative Agent and the other agents party thereto are party to a Credit Agreement, dated as of November 10, 2005 (as amended, modified or supplemented through the date hereof, the “Credit Agreement”);

          WHEREAS, the Borrower has requested that the Lenders agree to certain amendments to the Credit Agreement; and

          WHEREAS, the Borrower and the Lenders wish to amend the Credit Agreement as provided herein;

          NOW, THEREFORE, it is agreed:

     I. Amendments to the Credit Agreement

          1. Section 9.03(ii) of the Credit Agreement is hereby amended by deleting the text “$60,000,000” appearing therein and inserting the text “$74,000,000” in lieu thereof.

     II. Miscellaneous Provisions

          1. The Borrower hereby represents and warrants that (i) no Default or Event of Default exists as of the Fourth Amendment Effective Date (as defined below) both before and after giving effect to this Amendment and (ii) on the Fourth Amendment Effective Date, both before and after giving effect to this Amendment, all representations and warranties (other than those representations made as of a specified date) contained in the Credit Agreement and in the other Credit Documents are true and correct in all material respects.

          2. Each of the Credit Parties is duly organized, validly existing and in good standing under the laws of its jurisdiction of organization, and has the power, and has been duly authorized by all requisite action, to execute and deliver this Amendment and the other documents, agreements and instruments executed and delivered in connection herewith to which it is a party, and to perform its obligations hereunder and thereunder. This Amendment and the other documents, agreements and instruments executed and delivered in connection herewith have been duly executed and delivered by each of the applicable Credit Parties. This Amendment and the other documents, agreements and instruments executed and delivered in connection herewith are the legal, valid and binding obligations of each applicable Credit Party, enforceable against such Credit Party in accordance with their respective terms, except as such

enforceability may be limited by any applicable bankruptcy, insolvency, reorganization, moratorium or similar law affecting creditors’ rights generally (regardless of whether enforcement is sought at equity or at law).

          3. This Amendment shall become effective on the date (the “Fourth Amendment Effective Date”) on which each of the Required Lenders, the Borrower and each Subsidiary Guarantor shall have signed a counterpart hereof (whether the same or different counterparts) and shall have delivered (including by way of facsimile or other electronic transmission) the same to the Administrative Agent at White & Case LLP, 1155 Avenue of the Americas, New York, NY 10036, Attention: May Yip-Daniels (facsimile: 212-354-8113 / e-mail: myip@whitecase.com).

          4. This Amendment is limited as specified and shall not constitute a modification, acceptance or waiver of any other provision of the Credit Agreement or any other Credit Document.

          5. This Amendment may be executed in any number of counterparts and by the different parties hereto on separate counterparts, each of which counterparts when executed and delivered shall be an original, but all of which shall together constitute one and the same instrument. A complete set of counterparts shall be lodged with the Borrower and the Administrative Agent.

          6. THIS AMENDMENT AND THE RIGHTS AND OBLIGATIONS OF THE PARTIES HEREUNDER SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.

* * *

          IN WITNESS WHEREOF, the parties hereto have caused their duly authorized officers to execute and deliver this Amendment as of the date first above written.