                                                                     Exhibit 5.1

                                November 25, 2002

Pinnacle West Capital Corporation
400 North Fifth Street
Phoenix, Arizona 85004

     Re:  Registration Statement on Form S-3

Ladies and Gentlemen:

     We have acted as counsel to Pinnacle West Capital  Corporation,  an Arizona
corporation  (the  "Company"),   in  connection  with  the  preparation  of  the
Registration Statement on Form S-3 (the "Registration Statement") filed with the
Securities and Exchange Commission (the "Commission") by the Company on November
25, 2002. The Registration  Statement relates to the issuance and sale from time
to time,  pursuant to Rule 415 of the General Rules and Regulations  promulgated
under the  Securities  Act of 1933, as amended (the  "Securities  Act"),  of the
following  securities  with an aggregate  initial public offering price of up to
$600,000,000:  (i) common stock, no par value, of the Company ("Common  Stock");
(ii) one or more  classes or series of  preferred  stock,  no par value,  of the
Company ("Preferred Stock");  (iii) one or more series of debt securities of the
Company  ("Debt  Securities"),  consisting  of  debentures,  notes  and/or other
evidences  of   indebtedness,   which  may  be   unsubordinated   ("Senior  Debt
Securities")  or  subordinated  to  certain  other  obligations  of the  Company
("Subordinated Debt Securities");  (iv) purchase contracts obligating holders to
purchase  Securities  (as  hereinafter  defined)  at  a  future  date  or  dates
("Purchase Contracts");  and (vii) units comprised of one or more Securities (as
hereinafter  defined) in any combination  ("Units," and together with the Common
Stock, Preferred Stock, Debt Securities and Purchase Contracts, "Securities").

     Non-convertible  Senior Debt  Securities  will be issued under an Indenture
dated as of December 1, 2000 (For  Senior  Securities),  as amended by the First
Supplemental  Indenture  thereto  dated  as  of  March  15,  2001  (the  "Senior
Indenture"),  between  the  Company  and  The  Bank  of New  York,  as  trustee.
Convertible  Senior  Debt  Securities  will be  issued  under  an  indenture  in
substantially  the form filed as an exhibit to the  Registration  Statement (the
"Senior Convertible Indenture"),  entered into between the Company and a trustee
chosen by the Company and qualified to act as such under the Trust Indenture Act
of 1939, as amended (the "TIA") (the "Senior  Convertible  Indenture  Trustee").
Non-convertible  Subordinated  Debt Securities will be issued under an Indenture
dated as of  December  1,  2000 (For  Subordinated  Securities,  or, if  Article
Fourteen  is made  non-applicable  (as  permitted  by Section  301),  for Senior
Securities) (the "Subordinated Indenture"),  between the Company and The Bank of
New York, as trustee.  Convertible  Subordinated  Debt Securities will be issued
under an  indenture  in  substantially  the  form  filed  as an  exhibit  to the
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Pinnacle West Capital Corporation
November 25, 2002
Page 2

Registration Statement (the "Subordinated Convertible Indenture"),  entered into
between the Company and a trustee  chosen by the Company and qualified to act as
such  under the TIA (the  "Subordinated  Convertible  Indenture  Trustee").  The
Senior Indenture,  the Senior Convertible Indenture,  the Subordinated Indenture
and the Subordinated Convertible Indenture are sometimes hereinafter referred to
individually  as an  "Indenture"  and  collectively  as  the  "Indentures."  The
Purchase  Contracts will be issued under a purchase contract agreement in a form
that  will  be  filed  as  an  exhibit  to a  post-effective  amendment  to  the
Registration  Statement  or a  Current  Report on Form 8-K and  incorporated  by
reference in the Registration  Statement (a "Purchase Contract Agreement").  The
Units will be issued  under a unit  agreement in a form that will be filed as an
exhibit to a post-effective amendment to the Registration Statement or a Current
Report on Form 8-K and incorporated by reference in the  Registration  Statement
(a "Unit Agreement").

     This opinion is  delivered  in  accordance  with the  requirements  of Item
601(b)(5) of Regulation S-K under the  Securities  Act. We have examined (i) the
Registration  Statement;  (ii) the  Senior  Indenture;  (iii) the form of Senior
Convertible  Indenture;  (iv)  the  Subordinated  Indenture;  (v)  the  form  of
Subordinated  Convertible  Indenture;  (vi) the Amended and Restated Articles of
Incorporation  of  the  Company,  as  currently  in  effect  (the  "Articles  of
Incorporation");  (vii) the Bylaws of the  Company as  currently  in effect (the
"Bylaws");  and (viii) the resolutions  adopted by the Board of Directors of the
Company (the "Board") relating to the filing of the Registration  Statement (the
"Board  Resolutions").  We have also examined originals or copies,  certified or
otherwise  identified  to our  satisfaction,  of such records of the Company and
such agreements,  certificates of public officials,  certificates of officers or
other  representatives  of the  Company and  others,  and such other  documents,
certificates  and records as we have deemed  necessary or appropriate as a basis
for the opinions set forth herein.

     In our examination of the documents  referred to above, we have assumed (i)
the genuineness of the signatures not witnessed,  the  authenticity of documents
submitted as originals,  and the conformity to originals of documents  submitted
as  copies;  (ii) the legal  capacity  of all  natural  persons  executing  such
documents;  (iii) that such documents accurately describe and contain the mutual
understanding of the parties,  and that there are no oral or written  statements
or agreements that modify, amend, or vary, or purport to modify, amend, or vary,
any of the terms of such  documents;  (iv) as to documents  executed by entities
other than the  Company,  that each such  entity had the power to enter into and
perform its obligations under such documents,  and that such documents have been
duly authorized,  executed,  and delivered by, and are valid,  binding upon, and
enforceable against, such entities;  (v) that the parties to such documents will
receive no interest,  charges,  fees, or other benefits or  compensation  in the
nature of interest in connection with the transactions other than those that the
Company has agreed in writing in such  documents  to pay; and (vi) that no fraud
has occurred in connection with such  transactions.  As to any facts material to
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Pinnacle West Capital Corporation
November 25, 2002
Page 3

the  opinions  expressed  herein  which were not  independently  established  or
verified,  we have relied upon oral or written statements and representations of
officers and other representatives of the Company and others.

     In our  capacity  as your  counsel  in  connection  with  the  Registration
Statement,  we are familiar with the proceedings  taken and proposed to be taken
by  the  Company  in  connection  with  the   Registration   Statement  and  the
authorization and issuance of the Securities.  For purposes of this opinion,  we
have assumed that such  proceedings  will be timely and properly  completed,  in
accordance with all  requirements of applicable  United States federal,  Arizona
and New York laws.

     Based  upon the  foregoing  and in  reliance  thereon,  and  subject to the
qualifications and limitations set forth herein, we are of the opinion that:

     1. With  respect  to any  offering  of Common  Stock (the  "Offered  Common
Stock"),  the shares of the Offered  Common Stock  (including any Offered Common
Stock duly issued upon conversion, exchange or exercise of any other Securities)
will be duly authorized, validly issued, fully paid and nonassessable.

     2. With  respect  to any  offering  of any series of  Preferred  Stock (the
"Offered Preferred  Stock"),  when the Statement of Designations (as hereinafter
defined) has been duly filed with the Arizona Corporation Commission, the shares
of the Offered  Preferred  Stock  (including  any Offered  Preferred  Stock duly
issued upon conversion,  exchange or exercise of any other Securities),  will be
duly authorized, validly issued, fully paid and nonassessable.

     3. With  respect  to any  offering  of any series of Debt  Securities  (the
"Offered Debt Securities"), when (i) the applicable Indenture has been qualified
under  the  TIA and  duly  executed  and  delivered  by the  Company,  (ii)  the
applicable  trustee has been qualified  under the TIA and an applicable Form T-1
has been  properly  filed  with the  Commission,  and  (iii) in the case of Debt
Securities  to  be  issued  under  the  Senior  Convertible  Indenture  and  the
Subordinated Convertible Indenture, when such Indentures have been duly executed
and delivered by the Company and the Senior  Convertible  Indenture  Trustee and
Subordinated  Convertible  Indenture  Trustee,  respectively,  the Offered  Debt
Securities  (including any Offered Debt Securities duly issued upon  conversion,
exchange  or  exercise  of any  other  Securities)  will be  valid  and  binding
obligations of the Company,  enforceable  against the Company in accordance with
their terms.

     4. With  respect  to any  offering  of  Purchase  Contracts  (the  "Offered
Purchase  Contracts"),  when the  Purchase  Contract  Agreement  has  been  duly
executed and delivered by the Company and the other parties thereto, the Offered
Purchase  Contracts  will be  valid  and  binding  obligations  of the  Company,
enforceable against the Company in accordance with their terms.
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Pinnacle West Capital Corporation
November 25, 2002
Page 4

     5. With respect to any offering of any Units (the  "Offered  Units"),  when
the Unit  Agreement  relating to the Offered  Units has been duly  executed  and
delivered by the Company and the other parties  thereto,  the Offered Units will
be valid and binding obligations of the Company, enforceable against the Company
in accordance with their terms.

     The  opinions set forth  herein are subject to the  following  assumptions,
qualifications, limitations and exceptions being true and correct at or prior to
the time of the issuance and delivery of any Securities  offered pursuant to the
Registration Statement (collectively,  the "Offered Securities"): (i) the Board,
including any appropriate  committee appointed thereby, and appropriate officers
of the Company as contemplated in any Board resolutions authorizing the issuance
and sale of the Offered Securities, shall have duly established the terms of the
Offered  Securities and duly authorized and taken any other necessary  corporate
action to approve the  issuance and sale of the Offered  Securities  and related
matters  (including  without limitation with respect to Offered Preferred Stock,
the  execution,  acknowledgment  and filing of an  amendment  to the Articles of
Incorporation  in the form of a statement  pursuant to Arizona Revised  Statutes
Section  10-602  (the  "Statement  of  Designations")  in  accordance  with  the
applicable   provisions  of  Arizona  Revised  Statutes,   Title  10)  and  such
authorizations  and  actions  have not  been  rescinded;  (ii) the  terms of the
Offered  Securities and of their issuance and sale have been duly established in
conformity with such authorizations of the Board, the Articles of Incorporation,
the Bylaws,  any  applicable  Indenture,  Purchase  Contract  Agreement  or Unit
Agreement (collectively,  the "Applicable  Agreements"),  and any other relevant
agreement so as not to violate any applicable law, the Articles of Incorporation
or  the  Bylaws  (subject  to  the  further  assumption  that  the  Articles  of
Incorporation  and the Bylaws  have not been  amended  from the date hereof in a
manner that would affect the validity of any of the opinions  rendered  herein),
or result in a default under or breach of any  agreement or  instrument  binding
upon the Company and so as to comply with any  restriction  imposed by any court
or  governmental  body  having   jurisdiction   over  the  Company;   (iii)  the
consideration for the Offered  Securities is not less than the consideration for
which the Board of Directors  authorizes the issuance of such Offered Securities
and such  consideration  has been  received  by the  Company;  (iv) the  Offered
Securities (and, to the extent  necessary,  any securities which are a component
of the Offered  Purchase  Contracts or Units),  and any certificates or receipts
representing  the interests in the relevant Offered  Securities,  have been duly
authenticated, executed, countersigned, registered and delivered upon payment of
the  agreed-upon  consideration  therefor  and have been duly issued and sold in
accordance with any relevant agreement (including,  any Applicable  Agreements),
any underwriting  agreement with respect to the Offered  Securities or any other
duly authorized, executed and delivered,  applicable, valid and binding purchase
agreement,  or as otherwise  contemplated by the  Registration  Statement or any
post-effective   amendment  thereto,  and  any  Prospectus  Supplement  relating
thereto;  (v) the  Registration  Statement,  as finally  amended  (including all
necessary  post-effective  amendments) and any additional registration statement
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Pinnacle West Capital Corporation
November 25, 2002
Page 5

filed under Rule 462 will have been declared  effective under the Securities Act
and such  effectiveness  shall not have been  terminated or  rescinded;  (vi) an
appropriate  Prospectus Supplement will have been prepared,  delivered and filed
in compliance  with the Securities Act and the applicable  rules and regulations
thereunder describing the Offered Securities offered thereby;  (vii) the Offered
Securities will be issued and sold in compliance  with applicable  United States
federal  and  state  securities  laws and  solely  in the  manner  stated in the
Registration  Statement and the applicable  Prospectus Supplement and there will
not have  occurred  any change in law  affecting  the  validity of the  opinions
rendered  herein;  (viii) if the Offered  Securities  will be sold pursuant to a
firm commitment  underwritten  offering, the underwriting agreement with respect
to the Offered  Securities  in the form filed as an exhibit to the  Registration
Statement or any post-effective  amendment thereto or Current Report on Form 8-K
incorporated  by  reference  in  the  Registration  Statement,   has  been  duly
authorized, executed and delivered by the Company and the other parties thereto;
(ix) in the case of an Indenture,  Purchase Contract Agreement,  Unit Agreement,
Statement of Designation or other agreement or instrument  pursuant to which any
Securities  are to be issued,  there shall be no terms or  provisions  contained
therein which would affect the validity of any of the opinions  rendered herein;
and (x) in the case of issuance of Common  Stock or Preferred  Stock,  there are
sufficient  shares  of  Common  Stock or  Preferred  Stock,  as the case may be,
authorized by the Articles of Incorporation and unissued at such time.

     Members of our firm are  admitted to the Bar in the State of Arizona and we
do not  express any  opinion as to the laws of any  jurisdiction  other than the
laws of the State of Arizona and the laws of the United States of America to the
extent referred to specifically  herein.  In giving the above opinions,  we have
assumed  that the law of the  jurisdiction  or  jurisdictions  that  govern  the
Securities is substantially  the same as the law of the State of Arizona.  We do
not  express  any  opinion  with  respect to the  application  of the  Commodity
Exchange Act, as amended,  or the rules,  regulations or  interpretations of the
Commodity Futures Trading Commission to Securities,  the payment of principal or
interest  on which  will be  determined  by  reference  to one or more  currency
exchange  rates,   commodity  prices,  equity  indices  or  other  factors.  The
Securities may be issued from time to time on a delayed or continuous basis, but
this  opinion  is  limited  to the laws,  including  the  rules and  regulations
thereunder,  as in effect on the date  hereof.  We disclaim  any  obligation  to
advise you of any change in any of these sources of law or  subsequent  legal or
factual  developments  which  might  affect any  matters or  opinions  set forth
herein.

     The opinions set forth herein as to  enforceability  of  obligations of the
Company are subject to and limited by: (i) (a) general  principles  of equity or
by bankruptcy,  insolvency,  reorganization,  arrangement,  moratorium, or other
laws or  equitable  principles  relating  to or  affecting  the  enforcement  of
creditors' rights generally,  or by equitable principles that limit the right to
specific  performance or otherwise  limit remedial  action or the enforcement of
any security provided for the Securities,  (b) the necessity for compliance with
the statutory  procedural  requirements  governing the exercise of remedies by a
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Pinnacle West Capital Corporation
November 25, 2002
Page 6

secured creditor,  and (c) the qualification  that certain waivers,  procedures,
remedies,  and other provisions of the Securities may be unenforceable  under or
limited by the law of the State of  Arizona;  however,  such law does not in our
opinion substantially prevent the practical realization of the benefits thereof;
(ii)  provisions  of law which may  require  that a judgment  for money  damages
rendered  by a court in the United  States be  expressed  only in United  States
dollars;  (iii)  requirements  that a claim with respect to any Debt  Securities
denominated other than in U.S. dollars (or a judgment  denominated other than in
U.S.  dollars in respect of such claim) be converted into U.S. dollars at a rate
of exchange prevailing on a date determined pursuant to applicable law; and (iv)
governmental  authority  to limit,  delay or  prohibit  the  making of  payments
outside the United States or in foreign currency or composite  currency.  Rights
to indemnification and contribution may also be limited by United States federal
and state securities laws.

     We  express  no  opinion  as to the  validity,  legally  binding  effect or
enforceability of any provision in any agreement or instrument that (i) requires
or relates to payment of any  interest  at a rate or in an amount  which a court
would  determine in the  circumstances  under  applicable law to be commercially
unreasonable  or a penalty or a forfeiture  or (ii) relates to governing law and
submission by the parties to the jurisdiction of one or more particular courts.

     We hereby  consent to the filing of this  opinion  with the  Commission  as
Exhibit 5.1 to the Registration  Statement.  We also consent to the reference to
our firm under the heading "Legal  Opinions" in the Registration  Statement.  In
giving  this  consent,  we do not thereby  admit that we are in the  category of
persons whose consent is required  under Section 7 of the  Securities Act or the
rules and regulations of the Commission promulgated thereunder.

                                        Very truly yours,


                                        Snell & Wilmer LLP

