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                                                                     Exhibit 5.1

                     SANDERS, BARNET, GOLDMAN, SIMONS & MOSK
                           A PROFESSIONAL CORPORATION
                       1901 AVENUE OF THE STARS, SUITE 850
                          LOS ANGELES, CALIFORNIA 90067
                                 (310) 553-8011
                            TELECOPIER (310) 553-2435

                                October 28, 1997

2963.06.23.20B

Ameristar Casinos, Inc.
3773 Howard Hughes Parkway
Suite 490 South
Las Vegas, Nevada  89109

               RE:  $100,000,000 AGGREGATE PRINCIPAL AMOUNT OF
                     10 1/2% SENIOR SUBORDINATED NOTES DUE 2004 SERIES B

Ladies and Gentlemen:

        You have requested our opinion in connection with the registration of
$100,000,000 principal amount of 10 1/2% Senior Subordinated Notes due 2004
Series B (the "Exchange Notes"), by Ameristar Casinos, Inc., a Nevada
corporation (the "Company"), and the Subsidiary Guarantees (the "Subsidiary
Guarantees," and together with the Exchange Notes, the "Securities") by each of
Ameristar Casino Council Bluffs, Inc., an Iowa corporation ("ACCBI"), Ameristar
Casino Las Vegas, Inc., a Nevada corporation ("ACLVI"), Ameristar Casino
Vicksburg, Inc., a Mississippi corporation ("ACVI"), A.C. Food Services, Inc., a
Nevada corporation ("ACFS"), AC Hotel Corp., a Mississippi corporation ("ACHC,"
and collectively with ACCBI, ACLVI, ACVI and ACFS, the "Existing Guarantors")
and Cactus Pete's, Inc., a Nevada corporation ("CPI," and together with the
Existing Guarantors, the "Guarantors") pursuant to the Indenture dated as of
July 15, 1997, by and among the Company, First Trust National Association, as
Trustee (the "Trustee") and each of the Existing Guarantors, as amended and
supplemented by the Supplemental Indenture dated as of October 24, 1997, by and
among Company, the Trustee, the Existing Guarantors and CPI, under the
Securities Act of 1933, as amended (the "Act"), on Form S-4 filed with the
Securities and Exchange Commission (the "Commission") on August 26, 1997 (File
No. 333-34381), as amended by Amendment No. 1 to be filed with the Commission on
or about October 30, 1997 (the "Registration Statement").

        This opinion is being given solely in reliance on the attached opinion,
dated October 28, 1997, addressed to you from Latham & Watkins, special New York
Counsel to the Company and the Guarantors, and this opinion is subject to all
the qualifications, limitations and assumptions set forth in such opinion of
Latham & Watkins.

        We are opining herein as to the effect on the subject transactions only
of the internal laws of the State of New York (and only those of such laws that
are generally applicable to
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AMERISTAR CASINOS, INC.        OCTOBER 28, 1997                           PAGE 2

transactions of this type), and we express no opinion with respect to the
applicability thereto, or the effect thereon, of the laws of any other
jurisdiction or as to any matters of municipal law or the laws of any other
local agencies within any state.

        Subject to the foregoing and the other matters set forth herein, it is
our opinion that as of the date hereof:

               (1) The Exchange Notes, when executed, authenticated and
delivered by or on behalf of the Company in the manner described in the
Registration Statement, will constitute the valid and binding obligation of the
Company.

               (2) The Subsidiary Guarantees are the valid and binding
obligation of each of the Guarantors.

        The opinions rendered in paragraphs 1 and 2 relating to the valid and
binding nature of the Exchange Notes and the Subsidiary Guarantees are subject
to the following exceptions, limitations and qualifications:

               (i) the effect of bankruptcy, insolvency, reorganization,
moratorium or other similar laws now or hereafter in effect or relating to or
effecting the rights and remedies of creditors;

               (ii) the effect of general principles of equity, whether
enforcement is considered in a proceeding in equity or law, and the discretion
of the court before which any proceeding in equity or law may be brought;

               (iii) the unenforceability under certain circumstances under law
or a court decision of provisions providing for the indemnification of or
contribution to a party with respect to a liability where such indemnification
or contribution is contrary to public policy; and

               (iv) the effect on upstream guarantees and other aspects of the
transaction of Sections 547 and 548 of the federal Bankruptcy Code and
comparable provisions of state law (including without limitation, Article 10 of
the New York Debtor and Creditor Law).


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AMERISTAR CASINOS, INC.        OCTOBER 28, 1997                           PAGE 3

        We hereby consent to your filing this opinion as an exhibit to the
Registration Statement and to the reference to our firm contained in the
Registration Statement under the heading "Legal Matters." In giving this
consent, we do not admit that we are in the category of persons whose consent is
required under Section 7 of the Act or the rules and regulations of the
Commission promulgated thereunder.

                                 Very truly yours,

                                 Sanders, Barnet Goldman, Simons & Mosk
                                 A Professional Corporation


                                 By:    /s/ GORDON R. KANOFSKY
                                    --------------------------------------------
                                        Gordon R. Kanofsky
                                        Of Counsel
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                                LATHAM & WATKINS
                                ATTORNEYS AT LAW
                           53rd AT THIRD, SUITE 1000
                                885 THIRD AVENUE
                         NEW YORK, NEW YORK 10022-4802
                            TELEPHONE (212) 906-1200
                               FAX (212) 751-4864



                                October 28, 1997


                              FILE NO. 022908-0020

Ameristar Casinos, Inc.
3773 Howard Hughes Parkway
Suite 490 South
Las Vegas, Nevada  89109

                Re:  Exchange Notes; $100,000,000 Aggregate Principal
                     of Senior Subordinated Notes

Ladies and Gentlemen:

               You have requested our opinion in connection with the
registration of $100,000,000 principal amount of 10 1/2% Senior Subordinated
Notes due 2004 Series B (the "Exchange Notes"), by Ameristar Casinos, Inc., a
Nevada corporation (the "Company"), and the Subsidiary Guarantees (the
"Subsidiary Guarantees," and together with the Exchange Notes, the "Securities")
by each of Ameristar Casino Council Bluffs, Inc., an Iowa corporation ("ACCBI"),
Ameristar Casino Las Vegas, Inc., a Nevada corporation ("ACLVI"), Ameristar
Casino Vicksburg, Inc., a Mississippi corporation ("ACVI"), A.C. Food Services,
Inc., a Nevada corporation ("ACFS"), AC Hotel Corp., a Mississippi corporation
("ACHC," and collectively with ACCBI, ACLVI, ACVI and ACFS, the "Existing
Guarantors") and Cactus Pete's, Inc., a Nevada corporation ("CPI," and together
with the Existing Guarantors, the "Guarantors") pursuant to the Indenture dated
as of July 15, 1997, by and among the Company, First Trust National Association,
as Trustee (the "Trustee") and each of the Existing Guarantors (the "Original
Indenture"), as amended and supplemented by the Supplemental Indenture dated as
of October 24, 1997, by and among Company, the Trustee, the Existing Guarantors
and CPI (the "Supplemental Indenture," and together with the Original Indenture
and the Securities, the "Documents"), under the Securities Act of 1933, as
amended, on Form S-4 filed with the 

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LATHAM & WATKINS
Ameristar Casinos, Inc.
October 28, 1997
Page 2

Securities and Exchange Commission (the "Commission") on August 26, 1997 (File
No. 333-34381), as amended by Amendment No. 1 to be filed with the Commission on
or about October 30, 1997 (the "Registration Statement").

               In our capacity as your special New York counsel in connection
with such registration, we are familiar with the proceedings taken by the
Company and the Guarantors in connection with the authorization and issuance of
the Securities, and for the purposes of this opinion have assumed such
proceedings will be timely completed in the manner presently proposed. In
addition, we have made such legal and factual examinations and inquiries,
including an examination of originals or copies certified or otherwise
identified to our satisfaction of such documents, corporate records and
instruments, as we have deemed necessary or appropriate for purposes of this
opinion.

               In our examination, we have assumed the genuineness of all
signatures, the legal capacity of all natural persons executing documents, the
authority of all persons signing each of the documents on behalf of the parties
thereto, the authenticity of all documents submitted to us as originals, and the
conformity to authentic original documents of all documents submitted to us as
certified, conformed, telefacsimile or photostatic copies.

               We have been furnished with, and with your consent have relied
upon, certificates of officers or other representatives of the Company and each
of the Guarantors with respect to certain factual matters. In addition, we have
obtained and relied upon such certificates and assurances from public officials
as we have deemed necessary. We have relied, to the extent that we deem such
reliance proper, upon other statements of public officials and officers or other
representatives of the parties to the Documents and on the representations and
warranties set forth in the Documents, with respect to certain factual matters.

              We are opining herein as to the effect on the subject transactions
only of the internal laws of the State of New York (and only those of such laws
that are generally applicable to transactions of this type), and we express no
opinion with respect to the applicability thereto, or the effect thereon, of the
laws of any other jurisdiction or as to any matters of municipal law or the laws
of any other local agencies within any state. Furthermore, we call to your
attention that the Company and each of the Guarantors are located outside of the
State of New York and, accordingly, it may be necessary to seek execution or
enforcement of certain rights and remedies under the laws of such other
jurisdictions. We express no opinion whether or to what extent such other
jurisdictions would respect New York law.

               For purposes of this opinion, we have assumed, with your
permission, and without independent investigation or verification of any kind,
the following:
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LATHAM & WATKINS
Ameristar Casinos, Inc.
October 28, 1997
Page 3

               (i) Each of the parties to the Documents is duly organized,
validly existing and in good standing under the laws of its respective
jurisdiction of organization, with corporate or other organizational power and
authority and full legal right to conduct its business as now conducted and to
own, or hold under lease, its assets and to enter into the Documents to which it
is a party and perform its obligations thereunder;

               (ii) Each of the Documents has been duly authorized, executed and
delivered by each of the parties thereto;

               (iii) Neither the execution and delivery of each of the
Documents, the sale of each of the Securities, nor the performance by each such
party of its obligations under each of such Documents, contravenes or conflicts
with (a) its Articles of Association, or other applicable constituent documents,
as the case may be, (b) any law, rule or regulation binding upon it (including
any Federal, New York or other law with respect to the sale of securities), (c)
any agreement or instrument to which it is a party or by which its properties or
assets are bound, or (d) any judicial or administrative judgment, injunction,
order or decree that is binding upon it or its properties or assets;

               (iv) No order, consent, approval, license, authorization, or
validation of, or filing, recording or registration with, or exemption by, any
court, governmental body or authority, or any subdivision thereof, is required
to authorize, or is required in connection with, the execution and delivery of
the Documents by each of the parties thereto, or in connection with the
performance of each such party's obligations thereunder or the consummation of
the transactions contemplated thereby other than those that have been obtained
or made and are in full force and effect or will be obtained or made prior to
the time the same is required and thereafter remains in full force and effect;
and

               (v) Each of the Documents constitutes the legally valid and
binding obligations of each of the parties thereto (other than the Company and
each of the Guarantors), enforceable against such parties in accordance with
their respective terms.

               Except as otherwise expressly set forth herein, we express no
opinion as to compliance by any parties to the Securities with any local, state
or federal laws or regulations applicable to the subject transactions because of
the nature of their business.

               Subject to the foregoing and the other matters set forth herein,
it is our opinion that as of the date hereof:

               (1) The Exchange Notes, when executed, authenticated and
delivered by or on behalf of the Company in the manner described in the
Registration Statement, will constitute the valid and binding obligation of the
Company.


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LATHAM & WATKINS
Ameristar Casinos, Inc.
October 28, 1997
Page 4

               (2) The Subsidiary Guarantees are the valid and binding
obligation of each of the Guarantors.

               The opinions rendered in paragraphs 1 and 2 relating to the valid
and binding nature of the Exchange Notes and the Subsidiary Guarantees are
subject to the following exceptions, limitations and qualifications:

               (i) the effect of bankruptcy, insolvency, reorganization,
moratorium or other similar laws now or hereafter in effect or relating to or
effecting the rights and remedies of creditors;

               (ii) the effect of general principles of equity, whether
enforcement is considered in a proceeding in equity or law, and the discretion
of the court before which any proceeding in equity or law may be brought;

               (iii) the unenforceability under certain circumstances under law
or a court decision of provisions providing for the indemnification of or
contribution to a party with respect to a liability where such indemnification
or contribution is contrary to public policy; and

               (iv) the effect on upstream guarantees and other aspects of the
transaction of Sections 547 and 548 of the federal Bankruptcy Code and
comparable provisions of state law (including without limitation, Article 10 of
the New York Debtor and Creditor Law).

               To the extent that the obligations of the Company and the
Guarantors under the Indenture may be dependent upon such matters, we assume for
purposes of this opinion that the Trustee is duly qualified to engage in the
activities contemplated by the Indenture and that the Trustee has the requisite
organizational and legal power and authority to perform its obligations under
the Indenture. We have further assumed that the Trustee is in compliance,
generally and with respect to acting as trustee under the Indenture, with all
applicable laws and regulations.

               We consent to your filing this opinion as an exhibit to the
Registration Statement and to the reference to our firm contained in the
Registration Statement under the heading "Legal Matters." We further consent to
the reliance on this opinion by Sanders, Barnet, Goldman, Simons & Mosk, A
Professional Corporation, in connection with the opinion of such firm to you
being filed as an exhibit to the Registration Statement.

                                               Very truly yours,


                                               LATHAM & WATKINS