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                                                                     EXHIBIT 4.6

                                 --------------

                          First Supplemental Indenture

                            dated as of March 5, 1999

                               ------------------


                                with respect to:

                                    INDENTURE

                          Dated as of January 30, 1996

                         COAST HOTELS AND CASINOS, INC.
                                    as Issuer

                        13% FIRST MORTGAGE NOTES DUE 2002

                               COAST RESORTS, INC.
                                       and
                                COAST WEST, INC.
                                  as Guarantors

                         FIRSTAR BANK OF MINNESOTA, N.A.
                             as successor Trustee to
                       American Bank National Association




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        FIRST SUPPLEMENTAL INDENTURE dated as of March 5, 1999 (this
"Supplemental Indenture") between COAST HOTELS AND CASINOS, INC., a Nevada
corporation (the "Company"), COAST RESORTS, INC., a Nevada corporation ("Coast
Resorts"), as guarantor, COAST WEST, INC., a Nevada corporation ("Coast West"),
as guarantor (together with Coast Resorts, the "Guarantors") and FIRSTAR BANK OF
MINNESOTA, N.A., a national banking association organized under the laws of the
United States, as trustee (the "Trustee") for the securities issued under the
Indenture dated as of January 30, 1996 (the "Indenture") among the Company, the
Guarantors and the Trustee, as successor trustee to American Bank National
Association.

                                    Recitals

        A.      Pursuant to and in accordance with the terms of the Indenture
dated as of January 30, 1996, the Company established and issued debt securities
denominated as the "13% First Mortgage Notes due 2002" (the "Notes") and entered
into the related security documents (the "Security Documents"). Notes in the
aggregate principal amount of $175,000,000 are outstanding on the date of this
Supplemental Indenture.

        B.      In accordance with Section 9.02 of the Indenture, the Company
has obtained the written consent of the holders of Notes representing not less
than a majority in principal amount of the outstanding Notes to certain
amendments to the Indenture and the Security Documents.

        NOW, THEREFORE, THIS SUPPLEMENTAL INDENTURE WITNESSETH:

        For and in consideration of the premises herein contained and for other
good and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, it is mutually covenanted and agreed as follows:

                                   Agreements

        Section 1. Defined Terms. Capitalized terms not otherwise defined herein
shall have the meanings ascribed to them in the Indenture.

        Section 2. Condition to Effectiveness; Operative Date. This Supplemental
Indenture shall become effective as of the date hereof. The terms of this
Supplemental Indenture will become operative only upon acceptance by the Company
for payment of tendered Notes pursuant to the terms of the Company's Offer to
Purchase and Consent Solicitation Statement dated February 19, 1999, as such
offer may be amended from time to time. The date that this Supplemental
Indenture becomes operative shall be denominated herein as the "Operative Date."




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        Section 3. Amendment to Indenture.

        (a) The Indenture is hereby amended by deleting therefrom the following
provisions in their entirety:



        ----------------------------------------------------------------------------------------
        Existing Section Number          Caption
        ----------------------------------------------------------------------------------------
                                      
        Section 4.03                     SEC Reports
        ----------------------------------------------------------------------------------------
        Section 4.05                     Taxes
        ----------------------------------------------------------------------------------------
        Section 4.06                     Stay, Extension and Usury Laws
        ----------------------------------------------------------------------------------------
        Section 4.07                     Restricted Payments
        ----------------------------------------------------------------------------------------
        Section 4.08                     Dividend and Other Payment Restrictions Affecting
                                         Subsidiaries
        ----------------------------------------------------------------------------------------
        Section 4.09                     Incurrence of Indebtedness and Issuance of Preferred
                                         Stock
        ----------------------------------------------------------------------------------------
        Section 4.10                     Asset Sales
        ----------------------------------------------------------------------------------------
        Section 4.11                     Transactions with Affiliates
        ----------------------------------------------------------------------------------------
        Section 4.12                     Liens
        ----------------------------------------------------------------------------------------
        Section 4.13                     Line of Business
        ----------------------------------------------------------------------------------------
        Section 4.14                     Corporate Existence
        ----------------------------------------------------------------------------------------
        Section 4.15                     Change of Control
        ----------------------------------------------------------------------------------------
        Section 4.16                     Limitation on Issuances and Sales of Capital Stock of
                                         Wholly Owned Subsidiaries
        ----------------------------------------------------------------------------------------
        Section 4.17                     Subsidiary Guarantees
        ----------------------------------------------------------------------------------------
        Section 4.18                     Maintenance of Insurance
        ----------------------------------------------------------------------------------------
        Section 4.19                     Limitation on Status as Investment Company
        ----------------------------------------------------------------------------------------
        Section 4.20                     Further Assurances
        ----------------------------------------------------------------------------------------
        Section 4.21                     Limitations on Activities of Coast West
        ----------------------------------------------------------------------------------------
        Section 4.23                     Limitations on Use of Proceeds
        ----------------------------------------------------------------------------------------
        Section 4.24                     Limitations on Construction
        ----------------------------------------------------------------------------------------
        Section 4.25                     Payments for Consent
        ----------------------------------------------------------------------------------------
        Section 4.26                     Board of Directors
        ----------------------------------------------------------------------------------------
        Section 5.01                     Merger, Consolidation or Sale of Assets
        ----------------------------------------------------------------------------------------


        (b)     The Indenture is hereby amended by deleting therefrom
subsections (b) and (c) of Section 4.04 captioned "Compliance Certificate."

        (c)     The Indenture is hereby amended by deleting therefrom
subsections (v), (vi), (vii), (xi) and (xii) of Section 6.01 captioned "Events
of Default."



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        (d)     Each of the following provisions of the Indenture is hereby
renumbered as indicated below:



        -----------------------------------------------------------------------------------
        Existing Section Number      New Section Number     Caption
        -----------------------------------------------------------------------------------
                                                      
        4.04(a)                      4.03                   Compliance Certificate
        -----------------------------------------------------------------------------------
        4.22                         4.04                   No Amendment to Subordinate
                                                            Provisions
        -----------------------------------------------------------------------------------
        5.02                         5.01                   Successor Corporation
                                                            Substituted
        -----------------------------------------------------------------------------------
        6.01(viii)                   6.01(v)
        -----------------------------------------------------------------------------------
        6.01(ix)                     6.01(vi)
        -----------------------------------------------------------------------------------
        6.01(x)                      6.01(vii)
        -----------------------------------------------------------------------------------



        (e)     Any definitions used exclusively in the deleted provisions of
the Indenture set forth in paragraphs (a), (b) and (c) of this Section 3 are
hereby deleted in their entirety from the Indenture.

        (f)     Section 11.04 captioned "Guarantors May Consolidate, Etc., on
Certain Terms" is hereby amended and restated in its entirety as follows:

                "SECTION 11.04 GUARANTORS MAY CONSOLIDATE, ETC., ON CERTAIN
                TERMS.

                        (a)     Except as set forth in Articles 4 or 5 hereof
                and except for the merger of Coast West into the Company, no
                Guarantor shall consolidate with or merge with or into (whether
                or not such Guarantor is the surviving Person) another Person
                whether or not affiliated with such Guarantor unless (i) subject
                to the provisions of Section 11.05 hereof the Person formed by
                or surviving any such consolidation or merger (if other than
                such Guarantor) assumes, pursuant to a supplemental indenture
                and appropriate Security Documents in form and substance
                reasonably satisfactory to the Trustee, all the Obligations of
                such Guarantor under the Notes, the Indenture and the Security
                Documents; (ii) immediately after giving effect to such
                transaction, no Default or Event of Default exists; (iii) such
                Guarantor, or any Person formed by or surviving any such
                consolidation or merger, (A) would have Consolidated Net Worth
                (immediately after giving effect to such transaction) equal to
                or greater than the Consolidated Net Worth of such Guarantor
                immediately preceding the transaction and (B) except with
                respect to consolidations or mergers between Guarantors, would
                have a Fixed Charge Coverage Ratio (immediately after giving
                effect to such transaction) no lower than the Fixed Charge
                Coverage Ratio of such Guarantor immediately preceding the
                transaction; and (iv) such transaction will not result in the
                loss or suspension or material impairment of any material Gaming
                License. Such successor corporation thereupon may cause to be
                signed any or all of the Note Guarantees to be endorsed upon all
                of the Notes issuable hereunder which theretofore shall not have
                been signed by




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                the Company and delivered to the Trustee. All the Note
                Guarantees so issued shall in all respects have the same legal
                rank and benefit under this Indenture as the Note Guarantees
                theretofore and thereafter issued in accordance with the terms
                of this Indenture as though all of such Note Guarantees had been
                issued at the date of the execution hereof.

                        (b)     The Trustee, subject to the provisions of
                Section 11.05 hereof, shall be entitled to receive an Officers'
                Certificate and an Opinion of Counsel as conclusive evidence
                that any such consolidation, merger, sale or conveyance, and any
                such assumption of Obligations, comply with the provisions of
                this Section 11.04. Such certificate and opinion shall comply
                with the provisions of Section 12.05."

        (f)     Section 11.05 captioned "Releases of Note Guarantees" is hereby
amended and restated in its entirety as follows:

                "SECTION 11.05 RELEASES OF NOTE GUARANTEES.

                        In the event of a sale or other disposition of any
                Guarantor, by way of merger or consolidation, or a sale or other
                disposition of all of the Capital Stock of any Guarantor (other
                than the disposition of the Capital Stock of Coast West to the
                Company), then such Guarantor (in the event of a sale or other
                disposition, by way of such a merger, consolidation or
                otherwise, of all of the Capital Stock of such Guarantor) shall
                be released and relieved of any Obligations under its Note
                Guarantee; provided that (i) immediately after giving effect to
                such transaction, no Default or Event of Default shall have
                occurred and be continuing or would occur as a consequence
                thereof and (ii) the Net Proceeds of such sale or other
                disposition are applied in accordance with the applicable
                provisions of this Indenture. Coast West shall be released and
                relieved of any Obligations under its Note Guarantee at any time
                that it so elects; provided that Coast West has repaid to the
                Company in cash the aggregate amount of any Indebtedness owed to
                the Company by Coast West as of the date of such election and
                release. If Coast West merges with the Company and the Company
                is the surviving entity, then Coast West shall be automatically
                relieved of any Obligations under its Note Guarantee at the
                effective time of the merger. Upon delivery by the Company to
                the Trustee of an Officers' Certificate and Opinion of Counsel,
                to the effect that such sale or other disposition was made by
                the Company in accordance with the provisions of this Indenture,
                the Trustee shall execute any documents reasonably required in
                order to evidence the release of any such Guarantor from its
                obligations under its Note Guarantee. Any Guarantor not released
                from its obligations under its Note Guarantee shall remain
                liable for the full amount of principal of, premium and
                Liquidated Damages, if any, and interest on the Notes and for
                the other Obligations of any Guarantor under this Indenture as
                provided in this Article 11."



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        Section 4. Effective Date and Operative Date of this Supplemental
Indenture. This Supplemental Indenture shall be effective as of the date hereof
and shall be operative as of the Operative Date.

        Section 5. Indenture Ratified. Except as hereby otherwise expressly
provided, the Indenture is in all respects ratified and confirmed, and all the
terms, provisions and conditions thereof shall be and remain in full force and
effect.

        Section 6. Counterparts. This Supplemental Indenture may be executed in
any number of counterparts, each of which shall be an original, but such
counterparts shall together constitute but one and the same instrument.

        Section 7. Supplemental Indenture is an Amendment to Indenture. This
Supplemental Indenture is an amendment to the Indenture. The Indenture and this
Supplemental Indenture shall be read together from and after the Operative Date.

        Section 8. Governing Law. This Supplemental Indenture shall be governed
by and construed in accordance with the internal laws of the State of New York.



                     [Remainder of Page Intentionally Blank]





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        IN WITNESS WHEREOF, the parties hereto have caused this Supplemental
Indenture to be duly executed as of the day and year first above written.

                                        COAST HOTELS AND CASINOS, INC.


                                        By: /s/ MICHAEL J. GAUGHAN
                                           -------------------------------------
                                        Name:  Michael J. Gaughan
                                        Title: Chief Executive Officer

                                        COAST RESORTS, INC., as Guarantor


                                        By: /s/ MICHAEL J. GAUGHAN
                                           -------------------------------------
                                        Name:  Michael J. Gaughan
                                        Title: Chief Executive Officer

                                        COAST WEST, INC., as Guarantor


                                        By: /s/ MICHAEL J. GAUGHAN
                                           -------------------------------------
                                        Name:  Michael J. Gaughan
                                        Title: President

                                        FIRSTAR BANK OF MINNESOTA, N.A.,
                                        as Trustee


                                        By: /s/ FRANK P. LESLIE III
                                           -------------------------------------
                                        Name:  Frank P. Leslie III
                                        Title: Vice President



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