EXHIBIT 10.5

                          WAIVER AND SIXTH AMENDMENT TO

                                CREDIT AGREEMENT

         THIS WAIVER AND SIXTH  AMENDMENT TO CREDIT  AGREEMENT is made and dated
as of October 11, 2000 (the "Sixth  Amendment")  among SIERRA  HEALTH  SERVICES,
INC. (the "Company"), the Banks party to the Credit Agreement referred to below,
and BANK OF AMERICA,  N.A., a national banking  association,  as  Administrative
Agent (the  "Agent"),  and amends  that  certain  Credit  Agreement  dated as of
October  30,  1998,  as  amended by that  certain  First  Amendment  dated as of
November 23, 1998, that certain Second Amendment to Credit Agreement dated as of
January 15, 1999, that certain Third  Amendment to Credit  Agreement dated as of
December 14, 1999, that certain Waiver and Fourth  Amendment to Credit Agreement
dated as of August  14,  2000 and that  certain  Waiver and Fifth  Amendment  to
Credit  Agreement dated as of September 15, 2000 (as further amended or modified
from time to time, the "Credit Agreement").

                                    RECITALS

         WHEREAS,  the Company has requested  that the Agent and the Banks waive
certain  financial  covenants and amend  certain other  provisions of the Credit
Agreement,  and the Agent and the Banks are  willing  to do so, on the terms and
conditions specified herein;

         NOW, THEREFORE,  for good and valuable  consideration,  the receipt and
adequacy of which are hereby acknowledged, the parties hereby agree as follows:

     1.  Terms.  All terms used  herein  shall have the same  meanings as in the
Credit Agreement unless otherwise defined herein.

2. Waiver. By their execution  hereof,  the Banks hereby waive compliance by the
Company with Section  8.14(a) to (c)  inclusive of the Credit  Agreement for the
period from June 30, 2000 through  5:00 p.m.,  Eastern  Time,  October 31, 2000.
This waiver  shall be limited  precisely as provided for herein and shall not be
deemed to be a waiver or  modification  of any other  term or  provision  of the
Credit  Agreement or to be a consent to any other  transaction or further action
on the part of the Company or any of its  Subsidiaries  which would  require the
consent of the Banks under the Credit Agreement.

     3. Amendments. The Credit Agreement is hereby amended as follows:


     3.1 Amendment to Section 7.18.


     (a) Clause (c) of Section 7.18 of the Credit Agreement is hereby amended by
deleting the date  "October 11, 2000" and  replacing it with "October 31, 2000."

4.  Representations  and Warranties.  The Company represents and warrants to the
Agent and the Banks that, on and as of the date hereof,  and after giving effect
to this Sixth Amendment:

4.1  Authorization.  The execution,  delivery and  performance by the Company of
this Sixth Amendment has been duly authorized by all necessary corporate action,
and this Sixth Amendment has been duly executed and delivered by the Company.

4.2 Binding  Obligation.  This Sixth Amendment  constitutes the legal, valid and
binding obligation of the Company, enforceable against it in accordance with its
terms,  except  as  enforceability  may be  limited  by  applicable  bankruptcy,
insolvency,  or similar laws  affecting the  enforcement  of  creditors'  rights
generally or by equitable principles relating to enforceability.

4.3 No Legal Obstacle to Amendment.  The execution,  delivery and performance of
this Sixth Amendment will not (a) contravene the  Organization  Documents of the
Company; (b) constitute a breach or default under any contractual restriction or
violate or  contravene  any law or  governmental  regulation  or court decree or
order binding on or affecting the Company which individually or in the aggregate
does or could reasonably be expected to have a Material  Adverse Effect;  or (c)
result in, or require  the  creation  or  imposition  of, any Lien on any of the
Company's properties. No approval or authorization of any governmental authority
is required to permit the  execution,  delivery or performance by the Company of
this Sixth Amendment or the transactions contemplated hereby or thereby.

4.4 Incorporation of Certain  Representations.  After giving effect to the terms
of this Sixth Amendment,  the  representations and warranties of the Company set
forth in Article VI of the Credit Agreement are true and correct in all respects
on and as of the date hereof as though made on and as of the date hereof, except
to the extent such representations relate solely to an earlier specified date.

4.5  Default.  After  giving  effect to the terms of this  Sixth  Amendment,  no
Default  or Event of Default  under the Credit  Agreement  has  occurred  and is
continuing.

     5.  Conditions,  Effectiveness.  The  effectiveness of this Sixth Amendment
shall be subject to the  compliance  by the Company with its  agreements  herein
contained,  and to the delivery of the  following to Agent in form and substance
satisfactory to Agent on or before October 12, 2000:

     5.1 Execution of Sixth Amendment.  The Company,  the Agent and the Majority
Banks shall have signed a copy hereof and the same shall have been  delivered to
the Agent.

5.2 Security Agreement and Guaranty Affirmations.  The Agent shall have received
affirmation   letters  in  respect  of  the  Security  Agreement  and  Guaranty,
substantially in the form of Exhibit A, from each party thereto.

5.3 Fees and Expenses.  All invoiced fees and expenses of E&Y  Restructuring LLC
and all Attorney Costs of Mayer,  Brown & Platt shall have been paid or provided
for and,  after  giving  effect  thereto,  E&Y  Restructuring  LLC shall  hold a
retainer  in the  amount of  $100,000  and  Mayer,  Brown & Platt  shall  hold a
retainer in the amount of $100,000 for the payment of future fees and expenses.

     6. Miscellaneous.

6.1  Effectiveness  of the  Credit  Agreement  and the  Notes.  Except as hereby
expressly amended, the Credit Agreement,  the Loan Documents and the Notes shall
each remain in full force and effect,  and are hereby  ratified and confirmed in
all respects on and as of the date hereof.

6.2 Waivers. This Sixth Amendment is limited solely to the matters expressly set
forth herein and is specific in time and in intent and does not constitute,  nor
should it be construed as, a waiver or amendment of any other term or condition,
right,  power or privilege  under the Credit  Agreement or under any  agreement,
contract,  indenture,  document or  instrument  mentioned  therein;  nor does it
preclude or prejudice  any rights of the Agent or the Banks  thereunder,  or any
exercise  thereof or the exercise of any other right,  power or  privilege,  nor
shall it require the Majority Banks to agree to an amendment,  waiver or consent
for a similar  transaction or on a future occasion,  nor shall any future waiver
of any right,  power,  privilege or default  hereunder,  or under any agreement,
contract,  indenture,  document or instrument mentioned in the Credit Agreement,
constitute a waiver of any other right, power,  privilege or default of the same
or of any other term or provision.

6.3  Counterparts.  This  Sixth  Amendment  may be  executed  in any  number  of
counterparts,  and all of such  counterparts  taken  together shall be deemed to
constitute one and the same instrument.

     6.4 Governing Law. This Sixth  Amendment shall be governed by and construed
in accordance with the laws of the State of California.




                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]



<PAGE>



         IN WITNESS WHEREOF, the parties hereto have caused this Sixth Amendment
to be duly executed and delivered as of the date first written above.

                           SIERRA HEALTH SERVICES, INC.


                           By:     /s/  Anthony M. Marlon
                           Name:     Anthony M. Marlon
                           Title:      Chairman & CEO


<PAGE>


                           BANK OF AMERICA, N.A., as Administrative Agent


                           By:     /s/  David Price
                           Name:      David Price
                           Title:         Vice President

                           BANK OF AMERICA, N.A., as a Bank


                           By:      /s/  Clara Yang Strand
                           Name:       Clara Yang Strand
                           Title:          Managing Director

                           FIRST UNION NATIONAL BANK, as a Bank


                           By:     /s/  J. Matt Maclver, Jr.

                           Name:      J. Matt Maclver, Jr.

                           Title:        Vice President



                           CREDIT LYONNAIS NEW YORK BRANCH, as
                           a Bank

                           By:      /s/  Charles H. Heidsieck
                           Name:       Charles H. Heidsieck
                           Title:         Sr. Vice President



                           BANK ONE, NA, as a Bank


                           By:   /s/   Bonnie Wilson
                           Name:     Bonnie Wilson
                           Title:       First Vice President


<PAGE>



                           WELLS FARGO BANK, N.A., as a Bank


                           By:    /s/  Ernie Pinder
                           Name:     Ernie Pinder
                           Title:       Relationship Manager

                           UNION BANK OF CALIFORNIA, N.A., as a Bank

                           By:      /s/  Nancy A. Perkins
                           Name:       Nancy A. Perkins
                           Title:         Vice President



                           DEUTSCHE BANK AG, NEW YORK AND/OR CAYMAN
                           ISLANDS BRANCHES, as a Bank


                           By:    /s/  Ryan Zanin
                           Name:      Ryan Zanin
                           Title:        Managing Director

                           By:    /s/  David Mayhew
                           Name:     David Mayhew
                           Title:      Vice President


<PAGE>


                                                         EXHIBIT A to
                                                         Sixth Amendment
                                                         to Credit Agreement

                                October 11, 2000

Sierra Health-Care Options, Inc.
Nevada Administrators, Inc.
Behavioral Healthcare Options, Inc.
Sierra Home Medical Products, Inc.
Family Healthcare Services
Family Home Hospice, Inc.
Sierra Medical Management, Inc.
Sierra Health Holdings, Inc.
Southwest Medical Associates, Inc.
Northern Nevada Health Network, Inc.
Intermed, Inc.
Mohave Valley Hospital, Inc.
Tolemac, Inc.
M.E.G.A., Inc.
CII Financial, Inc.
Southwest Realty, Inc.
Prime Holdings, Inc.
c/o Sierra Health Services, Inc.
2724 North Tenaya Way
Las Vegas, Nevada 89128

        Re:     Sierra Health Services, Inc.

Gentlemen:

        Please refer to (1) the Credit Agreement,  dated as of October 30, 1998,
as amended by that certain First  Amendment  dated as of November 23, 1998, that
certain  Second  Amendment  dated as of January 15,  1999,  that  certain  Third
Amendment to Credit Agreement dated as of December 14, 1999, that certain Waiver
and Fourth  Amendment to Credit  Agreement  dated as of August 14, 2000 and that
certain Waiver and Fifth Amendment to Credit  Agreement dated a of September 15,
2000 (as so  amended,  the  "Credit  Agreement"),  by and  among  Sierra  Health
Services,  Inc., as the borrower,  the  commercial  lending  institutions  party
thereto  (collectively,  the  "Lenders")  and Bank of  America,  N.A.,  as agent
(herein, in such capacity, called the "Agent"), (2) the Security Agreement dated
August 23,  2000 from each of the  addressees  in favor of the  Lenders  and the
Agent (the "Security Agreement") and (3) the Guaranty dated August 23, 2000 from
each of the  addressees in favor of the Lenders and the Agent (the  "Guaranty").
Pursuant to a waiver and amendment dated of even date herewith,  a copy of which
is attached  hereto,  certain terms of the Credit  Agreement  were  amended.  We
hereby request that you (i) acknowledge and reaffirm all of your obligations and
undertakings  under the Security Agreement and Guaranty and (ii) acknowledge and
agree that the Security Agreement and Guaranty is and shall remain in full force
and effect in accordance with the terms thereof.

        Please  indicate your agreement to the foregoing by signing in the space
provided below, and returning the executed copy to the undersigned.

                                           BANK OF AMERICA, N.A., as Agent


                                           By:     /s/  David Price
                                           Title:      Vice President

Acknowledged and Agreed to
as of the date hereof

SIERRA HEALTH-CARE OPTIONS, INC.


By:    /s/  Wayne R. Nippe
   Its:        Secretary

NEVADA ADMINISTRATORS, INC.


By:   /s/  D. Sonenstein
   Its:       Secretary

BEHAVIORAL HEALTHCARE OPTIONS, INC.


By:   /s/  Steve Shoop
   Its:     Secretary

SIERRA HOME MEDICAL PRODUCTS, INC.


By:    /s/  Lynn Rosenbach
   Its:       Secretary

FAMILY HEALTHCARE SERVICES


By:   /s/  D. Sivertsen
   Its:      Secretary

FAMILY HOME HOSPICE, INC.


By:   /s/  D. Sivertsen
   Its:      Secretary

SIERRA MEDICAL MANAGEMENT, INC.


By:   /s/  Paul H. Palmer
   Its:       Secretary

SIERRA HEALTH HOLDINGS, INC.


By:   /s/  Erin MacDonald
   Its:      Secretary

SOUTHWEST MEDICAL ASSOCIATES, INC.


By:   /s/  James Marcotte
   Its:      Treasurer


<PAGE>


NORTHERN NEVADA HEALTH NETWORK, INC.


By:   /s/  David M. Marlon
   Its:      Secretary

INTERMED, INC.


By:   /s/  D. Sivertsen
   Its:      Secretary

MOHAVE VALLEY HOSPITAL, INC.


By:    /s/  David M. Marlon
   Its:       Secretary

TOLEMAC, INC.


By:   /s/  David M. Marlon
   Its:      Secretary

M.E.G.A., INC.


By:     /s/  Frank Collins
   Its:        Secretary

CII FINANCIAL, INC.


By:    /s/  D. Sonenstein
   Its:       Secretary


<PAGE>


SOUTHWEST REALTY, INC.


By:   /s/  Frank Collins
   Its:     Secretary

PRIME HOLDINGS, INC.


By:   /s/  Frank Collins
   Its:      Secretary