<PAGE>

                                                                     EXHIBIT 4.1

                                                                          PAGE 1

                                    DELAWARE
                                   ----------

                                 The First State

         I, HARRIET SMITH WINDSOR, SECRETARY OF STATE OF THE STATE OF DELAWARE,
DO HEREBY CERTIFY THE ATTACHED IS A TRUE AND CORRECT COPY OF THE CERTIFICATE OF
INCORPORATION OF "LAIDLAW INTERNATIONAL, INC." FILED IN THIS OFFICE ON THE
TWENTIETH DAY OF JUNE, A.D. 2003, AT 9:11 O'CLOCK A.M.

         A FILED COPY OF THIS CERTIFICATE HAS BEEN FORWARDED TO THE NEW CASTLE
COUNTY RECORDER OF DEEDS.

                                  /s/ Harriet Smith Windsor
                                  ----------------------------------------------
                                  Harriet Smith Windsor, Secretary of State

3617098 8100D [SEAL]              AUTHENTICATION: 2485142

030407841                                   DATE: 06-20-03

<PAGE>

                          CERTIFICATE OF INCORPORATION
                                       OF
                           LAIDLAW INTERNATIONAL, INC.

         Laidlaw International, Inc. hereby certifies as follows:

         First. The name of the corporation is Laidlaw International, Inc. (the
                  "Company").

         Second. The address of the Company's registered office in the State of
                  Delaware is 2711 Centerville Road, Suite 400, Wilmington,
                  Delaware 19805, County of New Castle. The name of the
                  Company's registered agent at such address is The Company
                  Corporation.

         Third. The purpose of the Company 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, as amended
                  (the "DGCL").

         Fourth. Section 1. Authorized Capital Stock. The Company is authorized
                  to issue two classes of capital stock, designated Common Stock
                  and Series A Junior Participating Preferred Stock. The total
                  number of shares of capital stock that the Company is
                  authorized to issue is 550,000,000 shares, consisting of
                  500,000,000 shares of Common Stock, par value $.01 per share
                  ("Common Stock"), and 50,000,000 shares of Series A Junior
                  Participating Preferred Stock, par value $.01 per share
                  ("Series A Preferred"). The shares of Series A Preferred may
                  only be issued pursuant to the Rights Agreement, dated as of
                  June 23, 2003, by and between the Company and Wells Fargo Bank
                  Minnesota, National Association, as rights agent, as may be
                  amended from time to time, or any successor rights agreement,
                  and any amendments thereto, that may be adopted by the Board
                  of Directors of the Company (the "Board").

         Section 2. Series A Preferred. (a) The holders of shares of Series A
Preferred, in preference to the holders of Common Stock, will be entitled to
receive, when, as and if declared by the Board, out of funds legally available
for the purpose, dividends payable in cash (except as otherwise provided below)
on such dates as are from time to time established for the payment of dividends
on the Common Stock (each such date being referred to herein as a "Dividend
Payment Date"), commencing on the first Dividend Payment Date after the first
issuance of a share or fraction of a share of Series A Preferred (the "First
Dividend Payment Date"), in an amount per share (rounded to the nearest cent)
equal to the greater of (i) $1.00 or (ii) subject to the provision for
adjustment hereinafter set forth, one hundred times the aggregate per share
amount of all cash dividends, and one hundred times the aggregate per share
amount (payable in kind)

<PAGE>

of all non-cash dividends, other than a dividend payable in shares of Common
Stock or a subdivision of the outstanding shares of Common Stock (by
reclassification or otherwise), declared on the Common Stock since the
immediately preceding Dividend Payment Date or, with respect to the First
Dividend Payment Date, since the first issuance of any share or fraction of a
share of Series A Preferred. In the event that the Company at any time (A)
declares a dividend on the outstanding shares of Common Stock payable in shares
of Common Stock, (B) subdivides the outstanding shares of Common Stock, (C)
combines the outstanding shares of Common Stock into a smaller number of shares
or (D) issues any shares of its capital stock in a reclassification of the
outstanding shares of Common Stock (including any such reclassification in
connection with a consolidation or merger in which the Company is the continuing
or surviving corporation), then, in each such case and regardless of whether any
shares of Series A Preferred are then issued or outstanding, the amount to which
holders of shares of Series A Preferred would otherwise be entitled immediately
prior to such event under clause (ii) of the preceding sentence will be adjusted
by multiplying such amount by a fraction, the numerator of which is the number
of shares of Common Stock outstanding immediately after such event and the
denominator of which is the number of shares of Common Stock that were
outstanding immediately prior to such event.

         (b)               The Company will declare a dividend on the Series A
                  Preferred as provided in the immediately preceding paragraph
                  immediately after it declares a dividend on the Common Stock
                  (other than a dividend payable in shares of Common Stock).
                  Each such dividend on the Series A Preferred will be payable
                  immediately prior to the time at which the related dividend on
                  the Common Stock is payable.

         (c)               Dividends will accrue on outstanding shares of Series
                  A Preferred from the Dividend Payment Date next preceding the
                  date of issue of such shares, unless (i) the date of issue of
                  such shares is prior to the record date for the First Dividend
                  Payment Date, in which case dividends on such shares will
                  accrue from the date of the first issuance of a share of
                  Series A Preferred, or (ii) the date of issue is a Dividend
                  Payment Date or is a date after the record date for the
                  determination of holders of shares of Series A Preferred
                  entitled to receive a dividend and before such Dividend
                  Payment Date, in either of which events such dividends will
                  accrue from such Dividend Payment Date. Accrued but unpaid
                  dividends will cumulate from the applicable Dividend Payment
                  Date but will not bear interest. Dividends paid on the shares
                  of Series A Preferred in an amount less than the total amount
                  of such dividends at the time accrued and payable on such
                  shares will be allocated pro rata on a share-by-share basis
                  among all such shares at the time outstanding. The Board may
                  fix a record date for the determination of holders of shares
                  of Series A Preferred entitled to receive payment of a
                  dividend or distribution declared thereon, which record date
                  will be not more than 60 calendar days prior to the date fixed
                  for the payment thereof.

                                        2

<PAGE>

         (d)               The holders of shares of Series A Preferred will have
                  the following voting rights:

                  (i)      Subject to the provision for adjustment hereinafter
                           set forth, each share of Series A Preferred will
                           entitle the holder thereof to one hundred votes on
                           all matters submitted to a vote of the stockholders
                           of the Company. In the event the Company at any time
                           (A) declares a dividend on the outstanding shares of
                           Common Stock payable in shares of Common Stock, (B)
                           subdivides the outstanding shares of Common Stock,
                           (C) combines the outstanding shares of Common Stock
                           into a smaller number of shares or (D) issues any
                           shares of its capital stock in a reclassification of
                           the outstanding shares of Common Stock (including any
                           such reclassification in connection with a
                           consolidation or merger in which the Company is the
                           continuing or surviving corporation), then, in each
                           such case and regardless of whether any shares of
                           Series A Preferred are then issued or outstanding,
                           the number of votes per share to which holders of
                           shares of Series A Preferred would otherwise be
                           entitled immediately prior to such event will be
                           adjusted by multiplying such number by a fraction,
                           the numerator of which is the number of shares of
                           Common Stock outstanding immediately after such event
                           and the denominator of which is the number of shares
                           of Common Stock that were outstanding immediately
                           prior to such event.

                  (ii)     Except as otherwise provided herein or by law, the
                           holders of shares of Series A Preferred and the
                           holders of shares of Common Stock will vote together
                           as one class on all matters submitted to a vote of
                           stockholders of the Company.

                  (iii)    Except as set forth herein, or as otherwise provided
                           by law, holders of Series A Preferred shall have no
                           voting rights.

         (e)               Whenever dividends or other dividends or
                  distributions payable on the Series A Preferred are in
                  arrears, thereafter and until all accrued and unpaid dividends
                  and distributions, whether or not declared, on shares of
                  Series A Preferred outstanding have been paid in full, the
                  Company will not:

                  (i)      declare or pay dividends, or make any other
                           distributions, on any shares of stock ranking junior
                           (either as to dividends or upon liquidation,
                           dissolution or winding up) to the shares of Series A
                           Preferred;

                  (ii)     declare or pay dividends, or make any other
                           distributions, on any shares of stock ranking on a
                           parity (either as to dividends or upon

                                        3

<PAGE>

                           liquidation, dissolution or winding up) with the
                           shares of Series A Preferred, except dividends paid
                           ratably on the shares of Series A Preferred and all
                           such parity stock on which dividends are payable or
                           in arrears in proportion to the total amounts to
                           which the holders of all such shares are then
                           entitled;

                  (iii)    redeem, purchase or otherwise acquire for
                           consideration shares of any stock ranking junior
                           (either as to dividends or upon liquidation,
                           dissolution or winding up) to the shares of Series A
                           Preferred; provided, however, that the Company may at
                           any time redeem, purchase or otherwise acquire shares
                           of any such junior stock in exchange for shares of
                           any stock of the Company ranking junior (either as to
                           dividends or upon dissolution, liquidation or winding
                           up) to the shares of Series A Preferred; or

                  (iv)     purchase or otherwise acquire for consideration any
                           shares of Series A Preferred or redeem, purchase or
                           otherwise acquire for consideration any shares of
                           stock ranking on a parity with the shares of Series A
                           Preferred, except in accordance with a purchase offer
                           made in writing or by publication (as determined by
                           the Board) to all holders of such shares upon such
                           terms as the Board, after consideration of the
                           respective annual dividend rates and other relative
                           rights and preferences of the respective Series and
                           classes, may determine in good faith will result in
                           fair and equitable treatment among the respective
                           series or classes.

         (f)               The Company will not permit any majority-owned
                  subsidiary of the Company to purchase or otherwise acquire for
                  consideration any shares of stock of the Company unless the
                  Company could, under paragraph (f) of this Section 2, purchase
                  or otherwise acquire such shares at such time and in such
                  manner.

         (g)               Any shares of Series A Preferred purchased or
                  otherwise acquired by the Company in any manner whatsoever
                  will be retired and canceled promptly after the acquisition
                  thereof. All such shares will upon their cancellation become
                  authorized but unissued shares of Preferred Stock and may be
                  reissued as Series A Preferred subject to the conditions and
                  restrictions on issuance set forth herein.

         (h)               Upon any liquidation, dissolution or winding up of
                  the Company, no distribution will be made (i) to the holders
                  of shares of stock ranking junior (either as to dividends or
                  upon liquidation, dissolution or winding up) to the shares of
                  Series A Preferred unless, prior thereto, the holders of
                  shares of Series A Preferred have received $100 per share,
                  plus an amount equal to accrued and unpaid dividends and
                  distributions thereon, whether or not declared, to the date of
                  such payment; provided, however, that the holders of shares of
                  Series A Preferred will be entitled to receive an

                                        4

<PAGE>

                  aggregate amount per share, subject to the provision for
                  adjustment hereinafter set forth, equal to one hundred times
                  the aggregate amount to be distributed per share to holders of
                  shares of Common Stock or (ii) to the holders of shares of
                  stock ranking on a parity (either as to dividends or upon
                  liquidation, dissolution or winding up) with the shares of
                  Series A Preferred, except distributions made ratably on the
                  shares of Series A Preferred and all such parity stock in
                  proportion to the total amounts to which the holders of all
                  such shares are entitled upon such liquidation, dissolution or
                  winding up. In the event the Company at any time (A) declares
                  a dividend on the outstanding shares of Common Stock payable
                  in shares of Common Stock, (B) subdivides the outstanding
                  shares of Common Stock, (C) combines the outstanding shares of
                  Common Stock into a smaller number of shares, or (D) issues
                  any shares of its capital stock in a reclassification of the
                  outstanding shares of Common Stock (including any such
                  reclassification in connection with a consolidation or merger
                  in which the Company is the continuing or surviving
                  corporation), then, in each such case and regardless of
                  whether any shares of Series A Preferred are then issued or
                  outstanding, the aggregate amount to which each holder of
                  shares of Series A Preferred would otherwise be entitled
                  immediately prior to such event under the proviso in clause
                  (i) of the preceding sentence will be adjusted by multiplying
                  such amount by a fraction, the numerator of which is the
                  number of shares of Common Stock outstanding immediately after
                  such event and the denominator of which is the number of
                  shares of Common Stock that were outstanding immediately prior
                  to such event.

         (i)               In the event that the Company enters into any
                  consolidation, merger, combination or other transaction in
                  which the shares of Common Stock are exchanged for or changed
                  into other stock or securities, cash or any other property,
                  then, in each such case, each share of Series A Preferred will
                  at the same time be similarly exchanged for or changed into an
                  amount per share, subject to the provision for adjustment
                  hereinafter set forth, equal to one hundred times the
                  aggregate amount of stock, securities, cash or any other
                  property (payable in kind), as the case may be, into which or
                  for which each share of Common Stock is changed or exchanged.
                  In the event the Company at any time (A) declares a dividend
                  on the outstanding shares of Common Stock payable in shares of
                  Common Stock, (B) subdivides the outstanding shares of Common
                  Stock, (C) combines the outstanding shares of Common Stock in
                  a smaller number of shares or (D) issues any shares of its
                  capital stock in a reclassification of the outstanding shares
                  of Common Stock (including any such reclassification in
                  connection with a consolidation or merger in which the Company
                  is the continuing or surviving corporation), then, in each
                  such case and regardless of whether any shares of Series A
                  Preferred are then issued or outstanding, the amount set forth
                  in the preceding sentence with respect to the exchange or
                  change of shares of Series A Preferred will be adjusted by
                  multiplying such amount by a fraction, the

                                        5

<PAGE>

                  numerator of which is the number of shares of Common Stock
                  outstanding immediately after such event and the denominator
                  of which is the number of shares of Common Stock that were
                  outstanding immediately prior to such event.

         (j)               The shares of Series A Preferred are not redeemable.

         (k)               Notwithstanding anything contained in this
                  Certificate of Incorporation to the contrary and in addition
                  to any other vote required by applicable law, this Certificate
                  of Incorporation may not be amended in any manner that would
                  materially alter or change the powers, preferences or special
                  rights of the Series A Preferred so as to affect them
                  adversely without the affirmative vote of the holders of at
                  least 66(Beta)% of the outstanding shares of Series A
                  Preferred, voting together as a single class, or, if no shares
                  of Series A Preferred are outstanding, of the outstanding
                  shares of Common Stock.

Section 3. Common Stock. Except as otherwise provided by law, the holders of
         Common Stock will be entitled to one vote on each matter submitted to a
         vote at a meeting of stockholders for each share of Common Stock held
         of record by such holder as of the record date for such meeting.

         FIFTH. The Board may make, amend and repeal the By-Laws of the Company.
                  Any By-Law made by the Board under the powers conferred hereby
                  may be amended or repealed by the Board (except as specified
                  in any such By-Law so made or amended) or by the stockholders
                  in the manner provided in the By-Laws of the Company.
                  Notwithstanding the foregoing and anything contained in this
                  Certificate of Incorporation to the contrary, By-Laws 1, 3, 8,
                  10, 11, 12, 13 and 50 may not be amended or repealed by the
                  stockholders and no provision inconsistent therewith may be
                  adopted by the stockholders or the Board, without the
                  affirmative vote of the holders of at least 66(Beta)% of the
                  voting power of the outstanding Voting Stock (as defined
                  below), voting together as a single class. Subject to the
                  immediately preceding sentence, the Company may in its By-Laws
                  confer powers upon the Board in addition to the foregoing and
                  in addition to the powers and authorities expressly conferred
                  upon the Board by applicable law. For the purposes of this
                  Certificate of Incorporation, "Voting Stock" means stock of
                  the Company of any class or series entitled to vote generally
                  in the election of the directors of the Board (the
                  "Directors"). Notwithstanding anything contained in this
                  Certificate of Incorporation to the contrary, the affirmative
                  vote of the holders of at least 66(Beta)% of the voting power
                  of the outstanding Voting Stock, voting together as a single
                  class, is required to amend or repeal, or to adopt any
                  provisions inconsistent with, this Article Fifth.

                                        6

<PAGE>

         SIXTH. Except as otherwise provided by law:

         (a)               any action required or permitted to be taken by the
                  stockholders of the Company must be effected at a duly called
                  annual or special meeting of stockholders of the Company and
                  may not be effected otherwise by any consent in writing of
                  such stockholders;

         (b)               special meetings of stockholders of the Company may
                  be called only by (i) the Chairman of the Board; (ii) the
                  President of the Company; (iii) the Secretary of the Company
                  within 10 calendar days after receipt of the written request
                  of a majority of the total number of Directors that the
                  Company would have if there were no vacancies; or (iv) persons
                  holding at least 66(Beta)% of all shares outstanding and
                  entitled to vote at such meeting; and

         (c)               stockholders will not be entitled to cumulative votes
                  in the election of Directors.

At any annual meeting or special meeting of stockholders of the Company, only
such business will be conducted or considered as has been brought before such
meeting in the manner provided in the By-Laws of the Company. Notwithstanding
anything contained in this Certificate of Incorporation to the contrary, the
affirmative vote of the holders of at least 66(Beta)% of the voting power of the
outstanding Voting Stock, voting together as a single class, will be required to
amend or repeal, or adopt any provision inconsistent with, this Article Sixth.

         SEVENTH. Section 1. Number, Election and Terms of Directors. The number
                  of the Directors of the Company shall be no less than seven
                  and no more than 15. If there are less than ten Directors of
                  the Company, no more than one Director may also be an employee
                  of the Company; and if there are ten or more Directors of the
                  Company, no more than two Directors may also be employees of
                  the Company. The Directors will be classified with respect to
                  the time for which they severally hold office into three
                  classes, as nearly equal in number as possible, designated
                  Class I, Class II and Class III. The Directors first appointed
                  to Class I will hold office for a term expiring at the annual
                  meeting of stockholders to be held in 2004, the Directors
                  first appointed to Class II will hold office for a term
                  expiring at the annual meeting of stockholders to be held in
                  2005 and the Directors first appointed to Class III will hold
                  office for a term expiring at the annual meeting of
                  stockholders to be held in 2006, with the members of each
                  class to hold office until their successors are elected and
                  qualified. At each annual meeting of the stockholders of the
                  Company, the successors to the class of Directors whose term
                  expires at that meeting will be elected by plurality vote of
                  all votes cast at such meeting to hold office for a term
                  expiring at the annual meeting of stockholders held in the
                  third year following the year of their election. Directors may
                  be

                                        7

<PAGE>

                  elected by the stockholders only at an annual meeting of
                  stockholders. Election of Directors of the Company must be by
                  written ballot.

Section 2. Nomination of Director Candidates. Advance notice of stockholder
         nominations for the election of Directors must be given in the manner
         provided in the By-Laws of the Company.

Section 3. Newly Created Directorships and Vacancies. Newly created
         directorships resulting from any increase in the number of Directors
         and any vacancies on the Board resulting from death, resignation,
         disqualification, removal or other cause will be filled solely by the
         affirmative vote of a majority of the remaining Directors then in
         office, even though less than a quorum of the Board, or by a sole
         remaining Director. Any Director elected in accordance with the
         preceding sentence will hold office for the remainder of the full term
         of the class of Directors in which the new directorship was created or
         the vacancy occurred and until such Director's successor has been
         elected and qualified. No decrease in the number of Directors
         constituting the Board may shorten the term of any incumbent Director.

Section 4. Removal. Any Director may be removed from office by the stockholders
         only for cause and only in the manner provided in this Section 4. At
         any annual meeting or special meeting of the stockholders, the notice
         of which states that the removal of a Director or Directors is among
         the purposes of the meeting, the affirmative vote of the holders of at
         least a majority of the voting power of the outstanding Voting Stock,
         voting together as a single class, may remove such Director or
         Directors for cause.

Section 5. Amendment, Repeal, Etc. Notwithstanding anything contained in this
         Certificate of Incorporation to the contrary, the affirmative vote of
         the holders of at least 66(Beta)% of the voting power of the
         outstanding Voting Stock, voting together as a single class, is
         required to amend or repeal, or adopt any provision inconsistent with,
         this Article Seventh. The amendment or repeal of, or the adoption of
         any provision inconsistent with, this Article Seventh must be by
         written ballot.

         EIGHTH. A Director shall not be personally liable to the Company or its
                  stockholders for monetary damages for breach of fiduciary duty
                  as a Director, except for liability (i) for any breach of the
                  Director's duty of loyalty to the Company or its stockholders,
                  (ii) for acts or omissions not in good faith or which involve
                  intentional misconduct or a knowing violation of law, (iii)
                  under Section 174 of the DGCL or (iv) for any transaction from
                  which the Director derived any improper personal benefit. If
                  the DGCL is amended after the filing of this Certificate of
                  Incorporation to authorize corporate action further
                  eliminating or limiting the personal liability of directors,
                  then the liability of a Director shall be

                                        8

<PAGE>

                  eliminated or limited to the fullest extent permitted by the
                  DGCL, as so amended. No modification or repeal of the
                  provisions of this Article Eighth shall adversely affect any
                  right or protection of any Director existing at the date of
                  such modification or repeal or create any liability or
                  adversely affect any such right or protection for any acts or
                  omissions of such director occurring prior to such
                  modification or repeal.

         NINTH. Each person who is or was or had agreed to become a Director or
                  officer of the Company and each such person who is or was
                  serving or who had agreed to serve at the request of the Board
                  or an officer of the Company as an employee or agent of the
                  Company or as a director, officer, employee or agent of
                  another corporation, partnership, joint venture, employee
                  benefit plan, trust or other entity, whether for profit or not
                  for profit (including the heirs, executors, administrators or
                  estate of such person), will be indemnified by the Company to
                  the full extent permitted by the DGCL or any other applicable
                  law as currently or hereafter in effect. The right of
                  indemnification provided in this Article Ninth will not be
                  exclusive of any other rights to which any person seeking
                  indemnification may otherwise be entitled, including without
                  limitation pursuant to any contract approved by a majority of
                  the whole Board (whether or not the Directors approving such
                  contract are or are to be parties to such contract or similar
                  contracts). Without limiting the generality or the effect of
                  the foregoing, the Company may adopt By-Laws, or enter into
                  one or more agreements with any person, that provide for
                  indemnification greater or different than that provided in
                  this Article Ninth or the DGCL. Any amendment or repeal of, or
                  adoption of any provision inconsistent with, this Article
                  Ninth will not adversely affect any right or protection
                  existing hereunder, or arising out of facts occurring, prior
                  to such amendment, repeal or adoption and no such amendment,
                  repeal or adoption will affect the legality, validity or
                  enforceability of any contract entered into or right granted
                  prior to the effective date of such amendment, repeal or
                  adoption.

         TENTH. The Company will not issue nonvoting capital stock to the extent
                  prohibited by section 1123 of Title 11 of the United States
                  Code as in effect on the effective date of the Plan of
                  Reorganization of Laidlaw USA, Inc. and its debtor affiliates
                  (the "Bankruptcy Code"); provided, however, that this Article
                  Tenth (a) will have no further force and effect beyond that
                  required under section 1123 of the Bankruptcy Code, (b) will
                  have such force and effect, if any, only for so long as such
                  section is in effect and applicable to the Company and (c) in
                  all events may be amended or eliminated in accordance with
                  applicable law as from time to time in effect.

                                        9

<PAGE>

         ELEVENTH. The name and address of the sole incorporator is as follows:

                                 Ivan R. Cairns
                                  Laidlaw Inc.
                             3221 North Service Road
                               Burlington, Ontario
                                 Canada L7R 3Y8

         TWELFTH. The following individuals shall serve as the initial directors
                  of the Company, and each individual shall hold office until
                  the annual meeting of stockholders to be held in the year set
                  forth next to such individual's name, or until his or her
                  successor is elected and qualified. The address of each
                  director is 55 Shuman Blvd, Naperville, Illinois 60563.

<TABLE>
<CAPTION>
         Name                                Term
-------------------------                    ----
<S>                                          <C>
    Kevin E. Benson                          2006
  John F. Chlebowski                         2004
James H. Dickerson, Jr                       2004
   Lawrence M. Nagin                         2006
   Vicki A. O'Meara                          2005
  Richard P. Randazzo                        2005
    Maria A. Sastre                          2004
    Peter E. Stangl                          2006
Carroll R. Wetzel, Jr.                       2005
</TABLE>

                                       10
<PAGE>

                  IN WITNESS WHEREOF, the undersigned, being the incorporator
hereinbefore named, has executed, signed and acknowledged this certificate of
incorporation this 20th day of June, 2003.

                                        /s/ Ivan R. Cairns
                                        -------------------------------------
                                        Ivan R. Cairns