UNLESS THIS  CERTIFICATE  IS PRESENTED BY AN  AUTHORIZED  REPRESENTATIVE  OF THE
DEPOSITORY  TRUST COMPANY,  A NEW YORK  CORPORATION  ("DTC"),  TO ARIZONA PUBLIC
SERVICE COMPANY OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR PAYMENT,
AND ANY  CERTIFICATE  ISSUED IS  REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH
OTHER  NAME AS IS  REQUESTED  BY AN  AUTHORIZED  REPRESENTATIVE  OF DTC (AND ANY
PAYMENT  IS MADE TO CEDE & CO. OR TO SUCH  OTHER  ENTITY AS IS  REQUESTED  BY AN
AUTHORIZED  REPRESENTATIVE  OF DTC), ANY TRANSFER , PLEDGE,  OR OTHER USE HEREOF
FOR  VALUE  OR  OTHERWISE  BY OR TO  ANY  PERSON  IS  WRONGFUL  INASMUCH  AS THE
REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.




                         ARIZONA PUBLIC SERVICE COMPANY

                           Floating Rate Note Due 2001

No. 1                                                               $250,000,000
                                                             CUSIP No. 040555BZ6

     Arizona Public Service  Company,  a corporation duly organized and existing
under the laws of Arizona (herein called the "Company",  which term includes any
successor  Person  under  the  Indenture  hereinafter  referred  to),  for value
received,  hereby  promises to pay to Cede & Co.,  or  registered  assigns,  the
principal sum of Two Hundred Fifty Million  Dollars on November 15, 2001, and to
pay  interest  thereon  from  November 8, 1999 or from the most recent  Interest
Payment Date to which interest has been paid or duly provided for,  quarterly in
arrears  on  February  15,  May 15,  August  15 and  November  15 in each  year,
commencing  February  15,  2000,  at the rate of LIBOR  plus  0.72%,  until  the
principal hereof is paid or made available for payment.

     The calculation  agent,  initially The Chase Manhattan Bank, will calculate
the interest  rate on this  Security.  The interest  rate will be equal to LIBOR
plus 0.72%.  The interest rate in effect for the period from November 8, 1999 to
February 15, 2000, the initial Interest Reset Date, will be LIBOR, as determined
on November 4, 1999, plus 0.72% (the "Initial  Interest Rate").  The calculation
agent will reset the interest rate on each Interest  Payment Date (each such day
an "Interest Reset Date").  The second London Business Day preceding an Interest
Reset Date will be the "Interest  Determination  Date" for that  Interest  Reset
Date. The interest rate in effect on each day that is not an Interest Reset Date
will be the  interest  rate  determined  as of the Interest  Determination  Date
pertaining to the immediately  preceding  Interest Reset Date. The interest rate
in effect on any day that is an Interest  Reset Date will be the  interest  rate
determined  as of the Interest  Determination  Date  pertaining to that Interest
Reset  Date,  except  that the  interest  rate in effect for the period from and
including  November 8, 1999 to the first Interest Reset Date will be the Initial
Interest Rate. The amount of interest payable for any period will be computed on
the basis of a  360-day  year for the  actual  number  of days  elapsed.  If any
Interest  Payment  Date (other than the Stated  Maturity  hereof or a Redemption
Date herefor) would  otherwise be a day that is not a Business Day, the Interest
Payment Date will be postponed to the next succeeding  Business Day, except that
if such Business Day falls in the next succeeding  calendar month, such Interest
Payment  Date shall be the  immediately  preceding  Business  Day. If the Stated
Maturity  hereof or any  Redemption  Date  herefor is not a Business  Day,  then
payment of principal and interest  payable on such date will be made on the next
succeeding  day which is a  Business  Day (and  without  any  interest  or other
payment  in  respect  of any such  delay),  in each case with the same force and
effect as if made on such date.  A "Business  Day" shall mean any day,  except a
Saturday,  a Sunday or a legal  holiday in The City of New York on which banking
institutions are authorized or required by law, regulation or executive order to
close;  provided that the day is also a London  Business Day.  "London  Business
Day" means any day on which  dealings in United States dollars are transacted in
the London interbank market.

     The  calculation  agent  will  determine  "LIBOR"  in  accordance  with the
following provisions:

     (i) With respect to any Interest Determination Date, LIBOR will be the rate
     for  deposits in United  States  dollars  having a maturity of three months
     commencing on the first day of the applicable  Interest Period that appears
     on  Telerate  Page 3750 as of 11:00 A.M.,  London  time,  on that  Interest
     Determination Date. If no rate appears,  LIBOR, in respect to that Interest
     Determination  Date,  will be determined in accordance  with the provisions
     described in (ii) below.

     (ii)  With  respect  to an  Interest  Determination  Date on  which no rate
     appears on Telerate Page 3750, as specified in (i) above,  the  calculation
     agent  will  request  the  principal  London  offices of each of four major
     reference  banks  in  the  London  interbank  market,  as  selected  by the
     calculation  agent,  to provide  the  calculation  agent  with its  offered
     quotation  for  deposits in United  States  dollars for the period of three
     months,  commencing on the first day of the applicable  Interest Period, to
     prime banks in the London  interbank  market at  approximately  11:00 A.M.,
     London time, on that Interest  Determination Date and in a principal amount
     that is representative for a single transaction in United States dollars in
     that market at that time. If at least two quotations

                                        2

     are provided,  then LIBOR on that Interest  Determination  Date will be the
     arithmetic  mean of those  quotations.  If fewer  than two  quotations  are
     provided,  then  LIBOR  on the  Interest  Determination  Date  will  be the
     arithmetic  mean of the rates quoted at  approximately  11:00 A.M.,  in The
     City of New York, on the Interest  Determination  Date by three major banks
     in The City of New York  selected  by the  calculation  agent  for loans in
     United  States  dollars to leading  European  banks,  having a  three-month
     maturity  and in a  principal  amount that is  representative  for a single
     transaction in United States dollars in that market at that time; provided,
     however,  that if the  banks  selected  by the  calculation  agent  are not
     providing  quotations  in the  manner  described  by this  sentence,  LIBOR
     determined as of that Interest  Determination  Date will be LIBOR in effect
     on that Interest Determination Date.

     "Telerate Page 3750" means the display  designated as "Page 3750" on Bridge
Telerate,  Inc., or any  successor  service,  for the purpose of displaying  the
London interbank rates of major banks for United States dollars.

     "Interest Period" means the period from and including November 8, 1999, to,
and  excluding,  the first Interest  Payment Date  thereafter and then from, and
including, the immediately preceding Interest Payment Date to which interest has
been paid or duly provided for to, but excluding, the next Interest Payment Date
or the Maturity hereof, as the case may be.

     The interest so payable,  and punctually  paid or duly provided for, on any
Interest Payment Date will, as provided in such Indenture, be paid to the Person
in  whose  name  this  Security  (or  one or  more  Predecessor  Securities)  is
registered  at the  close  of  business  on the  Regular  Record  Date  for such
interest,  which shall be the fifteenth  calendar day immediately  preceding the
Interest  Payment Date (whether or not a Business Day). Any such interest not so
punctually  paid or duly provided for will forthwith  cease to be payable to the
Holder on such Regular Record Date and may either be paid to the Person in whose
name this Security (or one or more Predecessor  Securities) is registered at the
close of  business on a Special  Record  Date for the payment of such  Defaulted
Interest to be fixed by the Trustee, notice whereof shall be given to Holders of
Securities  of this  series not less than 10 days prior to such  Special  Record
Date,  or be paid at any time in any other lawful manner not  inconsistent  with
the  requirements  of any  securities  exchange on which the  Securities of this
series may be listed,  and upon such notice as may be required by such exchange,
all as more fully provided in said Indenture.

     Payment of the principal of (and premium,  if any) and any interest on this
Security will be made at the office or agency of the Company maintained for that
purpose in The City of New York,  in such coin or currency of the United  States
of America as at the time of payment is legal  tender for  payment of public and
private debts;  provided,  however, that at the option of the Company payment of
interest  may be made by check  mailed to the  address  of the  Person  entitled
thereto as such address shall appear in the Security Register.

     Reference  is hereby made to the further  provisions  of this  Security set
forth on the reverse  hereof,  which further  provisions  shall for all purposes
have the same effect as if set forth at this place.

                                        3

     Unless the  certificate of  authentication  hereon has been executed by the
Trustee  referred to on the reverse  hereof by manual  signature,  this Security
shall  not be  entitled  to any  benefit  under  the  Indenture  or be  valid or
obligatory for any purpose.

     IN WITNESS  WHEREOF,  the  Company has caused  this  instrument  to be duly
executed under its corporate seal.

                                        ARIZONA PUBLIC SERVICE COMPANY


                                        By Michael V. Palmeri
                                           -------------------------------------
                                           Vice President, Finance

Attest:

Betsy A. Pregulman
- --------------------------------
Associate Secretary

                                        4

     This  Security  is one of a duly  authorized  issue  of  securities  of the
Company (herein called the "Securities"), issued and to be issued in one or more
series  under an  Indenture,  dated as of January  15, 1998  (herein  called the
"Indenture",  which  term  shall  have  the  meaning  assigned  to  it  in  such
instrument),  between  the  Company  and The Chase  Manhattan  Bank,  as Trustee
(herein  called the "Trustee",  which term includes any successor  trustee under
the Indenture), and reference is hereby made to the Indenture for a statement of
the respective rights,  limitations of rights,  duties and immunities thereunder
of the Company,  the Trustee and the Holders of the  Securities and of the terms
upon which the Securities are, and are to be, authenticated and delivered.  This
Security  is  one of the  series  designated  on the  face  hereof,  limited  in
aggregate principal amount to $250,000,000.

     The Securities of this series are subject to redemption  upon not less than
30 days' notice by mail at the option of the Company,  in whole or in part, from
time to time on any  Interest  Payment  Date on or after  November 15, 2000 at a
Redemption  Price equal to the principal amount of the Securities of this series
to be redeemed plus interest  accrued to the  Redemption  Date (the  "Redemption
Price") .

     If notice has been given as  provided  in the  Indenture  and funds for the
redemption of any  Securities  (or any portion  thereof)  called for  redemption
shall  have been made  available  on the  Redemption  Date  referred  to in such
notice,  such Securities (or any portion thereof) will cease to bear interest on
the date fixed for such  redemption  specified in such notice and the only right
of the Holders of such  Securities  will be to receive payment of the Redemption
Price.

     Notice of any  optional  redemption  of  Securities  of this series (or any
portion  thereof) will be given to Holders at their  addresses,  as shown in the
Security  Register for such  Securities,  not more than 60 nor less than 30 days
prior to the date fixed for  redemption.  The notice of redemption will specify,
among  other  items,  the  Redemption  Price  and the  principal  amount  of the
Securities  of this series held by such Holder to be redeemed.  If less than all
of the  Securities  of this  series  are to be  redeemed  at the  option  of the
Company,  the  Trustee  shall  select,  in such manner as it shall deem fair and
appropriate, the portion of such Securities to be redeemed in whole or in part.

     The Securities of this series will not be subject to any sinking fund.

     In the event of redemption of this Security in part only, a new Security or
Securities of this series and of like tenor for the  unredeemed  portion  hereof
will be issued in the name of the Holder hereof upon the cancellation hereof.

     If an Event of Default  with  respect to  Securities  of this series  shall
occur and be  continuing,  the principal of the Securities of this series may be
declared  due and  payable in the manner  and with the  effect  provided  in the
Indenture.

     The Indenture  permits,  with certain  exceptions as therein provided,  the
amendment  thereof and the  modification  of the rights and  obligations  of the
Company and the rights of the

                                        5

Holders of the  Securities of each series to be affected  under the Indenture at
any time by the Company and the Trustee  without the consent of such  Holders in
certain limited  circumstances  or with the consent of the Holders of 66-2/3% in
principal  amount of the Securities at the time Outstanding of each series to be
affected.  The Indenture  also  contains  provisions  permitting  the Holders of
specified  percentages  in principal  amount of the Securities of each series at
the time Outstanding, on behalf of the Holders of all Securities of such series,
to waive compliance by the Company with certain  provisions of the Indenture and
certain past  defaults  under the  Indenture  and their  consequences.  Any such
consent or waiver by the Holder of this Security shall be conclusive and binding
upon  such  Holder  and upon all  future  Holders  of this  Security  and of any
Security issued upon the  registration of transfer hereof or in exchange herefor
or in lieu  hereof,  whether or not  notation of such  consent or waiver is made
upon this Security.

     As provided in and subject to the provisions of the  Indenture,  the Holder
of this  Security  shall not have the right to  institute  any  proceeding  with
respect to the Indenture or for the  appointment of a receiver or trustee or for
any other remedy thereunder,  unless such Holder shall have previously given the
Trustee  written  notice of a  continuing  Event of Default  with respect to the
Securities of this series,  the Holders of not less than 25% in principal amount
of the Securities of this series at the time Outstanding shall have made written
request to the  Trustee  to  institute  proceedings  in respect of such Event of
Default as Trustee and offered the Trustee reasonable indemnity, and the Trustee
shall not have  received  from the Holders of a majority in principal  amount of
Securities of this series at the time Outstanding a direction  inconsistent with
such  request,  and shall have failed to institute any such  proceeding,  for 60
days after receipt of such notice, request and offer of indemnity. The foregoing
shall not apply to any suit  instituted  by the Holder of this  Security for the
enforcement of any payment of principal hereof or any premium or interest hereon
on or after the respective due dates expressed herein.

     No reference  herein to the  Indenture and no provision of this Security or
of the Indenture  shall alter or impair the obligation of the Company,  which is
absolute and unconditional, to pay the principal of and any premium and interest
on this  Security  at the times,  place and rate,  and in the coin or  currency,
herein prescribed.

     As provided in the Indenture and subject to certain limitations therein set
forth,  the transfer of this Security is registrable  in the Security  Register,
upon  surrender of this Security for  registration  of transfer at the office or
agency of the  Company in any place where the  principal  of and any premium and
interest on this  Security are payable,  duly endorsed by, or  accompanied  by a
written  instrument  of  transfer  in form  satisfactory  to the Company and the
Security  Registrar  duly  executed by, the Holder  hereof or his attorney  duly
authorized in writing,  and thereupon one or more new  Securities of this series
and of like  tenor,  of  authorized  denominations  and for the  same  aggregate
principal amount, will be issued to the designated transferee or transferees.

     The Securities of this series are issuable only in registered  form without
coupons  in  denominations  of $1,000  and any  integral  multiple  thereof.  As
provided in the Indenture and subject to certain  limitations therein set forth,
Securities of this series are exchangeable for a like aggregate principal amount
of  Securities  of this  series  and of like  tenor  of a  different  authorized
denomination, as requested by the Holder surrendering the same.

                                        6

     No service  charge shall be made for any such  registration  of transfer or
exchange,  but the Company may require  payment of a sum sufficient to cover any
tax or other governmental charge payable in connection therewith.

     Prior to due presentment of this Security for registration of transfer, the
Company,  the  Trustee and any agent of the Company or the Trustee may treat the
Person in whose name this  Security is  registered  as the owner  hereof for all
purposes,  whether or not this Security be overdue, and neither the Company, the
Trustee nor any such agent shall be affected by notice to the contrary.

     All terms used in this Security  which are defined in the  Indenture  shall
have the meanings assigned to them in the Indenture.

                                        7

                          CERTIFICATE OF AUTHENTICATION

     This is one of the Securities of the series designated  therein referred to
in the within-mentioned Indenture.

                                        THE CHASE MANHATTAN BANK
                                                                      AS TRUSTEE

                                        By T. J. Foley
                                           -------------------------------------
                                           AUTHORIZED OFFICER

                                        8