Exhibit 3.42
                          CERTIFICATE OF INCORPORATION
                                       OF
                     AMERICAN MEDICAL RESPONSE LEASING, INC.

1.   The name of this corporation is American Medical Response Leasing, Inc.

2.   The  registered  office of this  corporation  in the State of  Delaware  is
located at 1013 Centre Road,  in the City of  Wilmington,  County of New Castle.
The name of its registered agent at such address is Corporation Service Company.

3.   The purpose of this  corporation is to engage in any lawful act or activity
for which corporations may be organized under the General Corporation Law of the
State of Delaware.

4.   The  total  number of shares of stock  that  this  corporation  shall  have
authority  to issue is 3,000 shares of Common  Stock,  $.01 par value per share.
Each share of Common Stock shall be entitled to one vote.

5.   The name and mailing  address of the  incorporator  is:  Joshua T.  Gaines,
Ropes & Gray, One International Place, Boston, Massachusetts 02110.

6.   Except as  otherwise  provided in the  provisions  establishing  a class of
stock,  the number of  authorized  shares of any class or series of stock may be
increased  or  decreased  (but not below  the  number  of  shares  thereof  then
outstanding) by the affirmative  vote of the holders of a majority of the voting
power of the  corporation  entitled to vote  irrespective  of the  provisions of
Section 242(b)(2) of the General Corporation Law of the State of Delaware.

7.   The election of directors  need not be by written ballot unless the by-laws
shall so require.

8.   In furtherance  and not in limitation of the power conferred upon the board
of directors by law,  the board of  directors  shall have power to make,  adopt,
alter,  amend and repeal from time to time by-laws of this corporation,  subject
to the right of the stockholders  entitled to vote with respect thereto to alter
and repeal by-laws made by the board of directors.

9.   A director of this  corporation  shall not be liable to the  corporation or
its  stockholders  for  monetary  damages  for  breach  of  fiduciary  duty as a
director,  except to the extent that exculpation from liability is not permitted
under the General  Corporation  Law of the State of Delaware as in effect at the
time such  liability is  determined.  No amendment or repeal of this paragraph 9
shall apply to or have any effect on the  liability or alleged  liability of any
director of the corporation for or with respect to any acts or omissions of such
director occurring prior to such amendment or repeal.



10.  This  corporation  shall, to the maximum extent permitted from time to time
under the law of the  State of  Delaware,  indemnify  and upon  request  advance
expenses to any person who is or was a party or is threatened to be made a party
to any  threatened,  pending or completed  action,  suit,  proceeding  or claim,
whether civil, criminal,  administrative or investigative, by reason of the fact
that such  person is or was or has  agreed to be a  director  or officer of this
corporation  or while a director  or officer is or was serving at the request of
this corporation as a director,  officer, partner, trustee, employee or agent of
any  corporation,   partnership,  joint  venture,  trust  or  other  enterprise,
including  service  with respect to employee  benefit  plans,  against  expenses
(including  attorney's  fees and  expenses),  judgments,  fines,  penalties  and
amounts paid in settlement incurred (and not otherwise  recovered) in connection
with the investigation,  preparation to defend or defense of such action,  suit,
proceeding or claim;  provided,  however,  that the foregoing  shall not require
this  corporation  to indemnify or advance  expenses to any person in connection
with any action,  suit,  proceeding,  claim or  counterclaim  initiated by or on
behalf of such  person.  Such  indemnification  shall not be  exclusive of other
indemnification rights arising under any by-law, agreement, vote of directors or
stockholders  or otherwise and shall inure to the benefit of the heirs and legal
representatives  of such person. Any person seeking  indemnification  under this
paragraph  10 shall be deemed to have met the  standard of conduct  required for
such  indemnification  unless the contrary shall be  established.  Any repeal or
modification  of the  foregoing  provisions  of  this  paragraph  10  shall  not
adversely  affect  any right or  protection  of a  director  or  officer of this
corporation  with respect to any acts or  omissions of such  director or officer
occurring prior to such repeal or modification.

11.  The books of this  corporation may (subject to any statutory  requirements)
be kept  outside  the State of  Delaware  as may be  designated  by the board of
directors or in the by-laws of this corporation.

12.  If at any time  this  corporation  shall  have a class of stock  registered
pursuant to the provisions of the  Securities  Exchange Act of 1934, for so long
as such class is so  registered,  any action by the  stockholders  of such class
must be taken at an annual or  special  meeting of  stockholders  and may not be
taken by written consent.

13.  The effective date of the formation of this corporation shall be January 1,
1997.

THE UNDERSIGNED,  the sole incorporator  named above,  hereby certifies that the
facts stated above are true as of this 31st day of December, 1996.

                                           /s/ Joshua T. Gaines
                                           -------------------------------------
                                           Joshua T. Gaines
                                           Sole Incorporator

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                            CERTIFICATE OF AMENDMENT
                                       OF
                          CERTIFICATE OF INCORPORATION

     American  Medical  Response  Leasing,  Inc., a  corporation  organized  and
existing  under  and by virtue of the  General  Corporation  Law of the State of
Delaware, DOES HEREBY CERTIFY:

     FIRST:  That the Sole Director of said  corporation  has adopted by written
consent the following resolution:

     RESOLVED: That it is advisable and in the best interest of this Corporation
               that  Article  1 of the  Certificate  of  Incorporation  of  this
               Corporation be amended to read in its entirety as follows:

     1. The name of this corporation is American Medical Response Holdings, Inc.

     SECOND: That the said amendment has been consented to and authorized by the
holder of a majority  of the issued and  outstanding  stock  entitled to vote by
written  consent given in accordance  with the  provisions of Section 228 of the
General Corporation Law of the State of Delaware.

     THIRD: That the aforesaid amendment was duly adopted in accordance with the
applicable  provisions of Section 242 and 228 of the General  Corporation Law of
the State of Delaware.

     IN WITNESS  WHEREOF,  said  corporation  has caused this  certificate to be
signed by Joshua T. Gaines, its Vice President, this 31 of January, 1999.

                                        AMERICAN MEDICAL RESPONSE LEASING, INC.

                                                By:  /s/ Joshua T. Gaines
                                           -------------------------------------
                                                     Vice President

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                    CERTIFICATE OF CHANGE OF REGISTERED AGENT

                                       AND

                                REGISTERED OFFICE

                                    * * * * *

     American  Medical  Response  Holdings,  Inc., a  corporation  organized and
existing  under  and by virtue of the  General  Corporation  Law of the State of
Delaware, DOES HEREBY CERTIFY:

     The present  registered  agent of the  corporation is  Corporation  Service
Company and the present registered office of the corporation is in the county of
New Castle.

     The Board of Directors of American Medical Response Holdings,  Inc. adopted
the following resolution on the 8th day of March, 1999.

     Resolved, that the registered office of American Medical Response Holdings,
Inc. in the state of Delaware be and it hereby is changed to  Corporation  Trust
Center, 1209 Orange Street, in the City of Wilmington, County of New Castle, and
the authorization of the present registered agent of this corporation be and the
same is hereby  withdrawn,  and THE CORPORATION  TRUST COMPANY,  shall be and is
hereby constituted and appointed the registered agent of this corporation at the
address of its registered office.

     IN WITNESS WHEREOF,  American Medical  Response  Holdings,  Inc. has caused
this statement to be signed by Joshua T. Gaines,  its Vice President,  this 15th
day of March, 1999.

                                           /s/ Joshua T. Gaines
                                           -------------------------------------
                                           Joshua T. Gaines, Vice President

(DEL. - 264 - 6/15/94)

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