<PAGE>

                                                                    EXHIBIT 10.1

                        WAIVER AND AMENDMENT AGREEMENT


      THIS WAIVER AND AMENDMENT AGREEMENT (this "Agreement") is entered into on
                                                 ---------                     
September 23, 1998 among Medical Resources, Inc. (the "Company") and the
                                                       -------          
institutional investors party hereto (the "Purchasers").  The Purchasers are
                                           ----------                       
collectively the holders of $52,000,000 in aggregate principal amount of the
Company's 7.77% Senior Notes due February 20, 2005 (the "7.77 Notes") issued
                                                         ----------         
pursuant to a Note Purchase Agreement dated as of February 20, 1997 (the
"February Note Agreement"), $20,000,000 in aggregate principal amount of the
------------------------                                                    
Company's 8.10% Senior Notes due February 20, 2005 (the "8.10% Notes") and
                                                         -----------      
$6,000,000 in aggregate principal amount of the Company's 8.01% Senior Notes due
February 20, 2005 (the "8.01% Notes" and together with the 7.77% Notes and the
                        -----------                                           
8.10% Notes, the "Notes") issued pursuant to a Note Purchase Agreement dated as
                  -----                                                        
of June 26, 1997 (the "June Note Agreement" and together with the February Note
                       -------------------                                     
Agreement, the "Note Agreements").  Capitalized terms not otherwise defined in
                ---------------                                               
this Agreement have the meanings given therefor in the Note Agreements.

      The Company has advised the Purchasers that it is not currently in
compliance with certain of its covenants set forth in the Note Agreements and
that it is or may be obligated to make payments in connection with its
Repurchase Obligations (as defined in Section 2(6) below) which, if made, would
constitute Restricted Payments not permitted under paragraph 6B of the Note
Agreements.  The Company has requested that the Purchasers waive the Company's
covenant defaults through the date hereof, waive any default under paragraph 6B
of the Note Agreements as a result of it making such Restricted Payments and to
otherwise amend certain of its financial covenants.  The Purchasers are willing
to do so on the terms and conditions of this Agreement.
 
      NOW, THEREFORE, the parties agree:

      1.   WAIVERS. Subject to the delivery by the Company of the items set
forth in Section 4, the Purchasers hereby waive:

      (1) all Defaults and Events of Default under the Note Agreements arising
out of the Company's failure to comply with its covenants set forth in
paragraphs 5 and 6 thereof occurring prior to the date hereof provided such
                                                              --------     
waiver shall not constitute a waiver of any Default or Event of Default
occurring or continuing on or after the date hereof under the Note Agreements,
after giving effect to the amendments contemplated hereby, the Waiver granted by
the Purchasers on June 25, 1998 and the Consent granted by the Purchasers on
August 12, 1998.

      (2) any Make Whole Amount which would otherwise be due pursuant to
paragraph 4A of the Note Agreements as a result of the prepayment of principal
required under Section 4(1) and any requirement under the Note Agreements that
such prepayment of principal be applied against the Company's obligation to make
scheduled payments of principal on the Notes other than in accordance with such
Section 4(1).

      2.   AMENDMENT TO NOTE AGREEMENTS.  Subject to the delivery by the Company
of the items set forth in Section 4, the Note Agreements are hereby amended:

      (1)  Interest Rate.
           ------------- 

      (a)  From and after July 25, 1998, the 7.77% Notes shall bear interest on
the unpaid principal balance at the annual rate of 8.8969%, the 8.10% Notes
shall bear interest on the unpaid principal balance at the annual rate of
9.2269% and the 8.01% Notes shall bear interest at the annual rate of 9.1369%
and each of the Notes shall bear interest on overdue principal, overdue Make
Whole Amount and, to the extent permitted by law, overdue interest at a rate
which is 200 
<PAGE>
 
                                      -2-



basis points over the then applicable rate of interest under such Note for
principal not overdue. From and after August 20, 1998, accrued interest on the
Notes will be due and payable monthly in arrears on the 20th day of each month
commencing September 20, 1998.

      (b)  If the aggregate amount of cash payments by the Company or its
Restricted Subsidiaries on the Contingent Obligations (as defined in Section
2(6))  made between June 30, 1998 and (i) December 31, 1998 exceeds $4,000,000,
(ii)  March 31, 1999 exceeds $6,000,000, or (iii) June 30, 1999, exceeds
$8,000,000 (such amounts being "Target Amounts"), the annual rate of interest on
                                --------------                                  
the Notes  (as previously adjusted pursuant to subparagraph (a) of this Section
2(1)) shall be increased by an additional 50 basis points from and after the
date on which the applicable Target Amount is first exceeded, provided, if the
                                                              --------        
interest rate on the Notes has been increased as a result of cash payments on
the Contingent Obligations exceeding the Target Amounts during the period ending
December 31, 1998 or during the period ending March 31, 1999 but at June 30,
1999 the aggregate amount of cash payments on the Contingent Obligations from
June 30, 1998 through June 30, 1999 does not exceed $8,000,000 for such period,
the annual rate of interest on the Notes shall be reduced from and after June
30, 1999 to 15 basis points over the interest rates set forth in subparagraph
(a) of this Section 2(1).

      (2) Calculation of Make Whole Amount.  Notwithstanding the increase in
          --------------------------------                                  
interest rates provided for in Section 2(1),  the amount of interest which would
have accrued on Called Principal if such Called Principal were not paid prior to
its scheduled due date for the purposes of determining the Make Whole Amount due
on any prepayment or acceleration of the Notes shall be calculated using the
interest rates set forth in the Note Agreements prior to this Agreement.

      (3) Reporting.  The following clause (x) is added to paragraph 5A:
          ---------                                                     

           "(x) promptly, but not later than 20 days following the end of each
      calendar month, a cash flow report for such month accompanied by a
      reconciliation of the actual versus projected cash flows and promptly, but
      not later than the seventh day following the end of each second week
      through September 30, 1998, a cash flow report for such biweekly period."

      (4) Financial Covenants.  Paragraphs 6A(2), 6A(3) and 6A(4) are deleted
          -------------------                                                
and the following substituted therefor:

           "6A(2)  INTEREST EXPENSE COVERAGE.  As of the last day of any fiscal
      quarter ending on or after September 30, 1998, the ratio of (a)
      Consolidated EBITA to (b) Consolidated Interest Expense, for the three
      most recently ended fiscal quarters taken as a single accounting period in
      the case of the quarter ended September 30, 1998 and, thereafter, for the
      four most recently ended fiscal quarters taken as a single accounting
      period, shall not be less than the ratio specified below for such fiscal
      quarter:

<TABLE>
<CAPTION>
          Fiscal Quarters Ending                 Ratio
          ----------------------                 -----
          <S>                                 <C>
 
          September 30, 1998                  1.43 to 1.00
 
          December 31, 1998                   1.56 to 1.00
 
          March 31, 1999                      1.82 to 1.00
 
          June 30, 1999                       2.02 to 1.00
</TABLE> 
<PAGE>
 
                                      -3-

<TABLE> 
          <S>                                 <C> 
          September 30, 1999                  2.20 to 1.00
 
          December 31, 1999 and any
          fiscal quarter ending thereafter    2.25 to 1.00
</TABLE>

          6A(3)  LIMITATION ON CONSOLIDATED TOTAL DEBT.

          (a) The Company shall not permit on, or at any time from and after the
     date hereof through, September 30, 1998, Total Debt to exceed 54.02% of
     Consolidated Total Capitalization.

          (b)  The Company and the Restricted Subsidiaries shall not incur,
     create, issue, assume, guarantee or otherwise become liable in respect of
     any Debt after September 30, 1998 unless (i) no Default or Event of Default
     exists immediately before or immediately after the incurrence of such Debt
     or would otherwise reasonably be expected to result therefrom; and (ii)
     immediately after giving effect to the incurrence of such Debt on a pro
     forma basis, Total Debt does not exceed the applicable percentage set forth
     below of Consolidated Total Capitalization determined as of the most recent
     fiscal quarter end:

<TABLE>
<CAPTION>
---------------------------------------------------------------------
        DATE DEBT IS INCURRED          PERCENTAGE OF CONSOLIDATED
        ---------------------             TOTAL CAPITALIZATION
                                       ---------------------------
---------------------------------------------------------------------
<S>                                    <C>
 On or after September 30, 1998 but                          54.02%
 prior to December 31, 1998
---------------------------------------------------------------------
 On or after December 31, 1998 but                           51.62%
 prior to March 31, 1999
---------------------------------------------------------------------
 On or after March 31, 1999 but                              50.61%
 prior to June 30, 1999
---------------------------------------------------------------------
 On or after June 30, 1999 but prior                         49.50%
 to September 30, 1999
---------------------------------------------------------------------
 On or after September 30, 1999 but                          48.29%
 prior to December 31, 1999
---------------------------------------------------------------------
 On or after December 31, 1999 but                           47.04%
 prior to March 31, 2000
---------------------------------------------------------------------
 On or after March 31, 2000                                  52.50%
---------------------------------------------------------------------
</TABLE>

          For the purposes of this PARAGRAPH 6A(3):  (i) the outstanding Debt of
     any Person which becomes a Restricted Subsidiary after June 30, 1998 shall
     be deemed to have been incurred at the time it becomes a Restricted
     Subsidiary; (ii) if any outstanding Debt of the Company owned by a
     Restricted Subsidiary or any outstanding Debt of a Restricted Subsidiary
     owned by the Company or another Restricted Subsidiary is sold or otherwise
     transferred to a Person who is not the Company or a Restricted Subsidiary,
     such Debt shall be deemed to have been incurred on the date of such sale or
     transfer; (iii) any Debt which is extended, renewed or refunded or
     refinanced after the Closing Date shall be deemed incurred on the date of
     such extension, renewal, refunding or refinancing; (iv) in making any
<PAGE>
 
                                      -4-

     determination of Consolidated Total Capitalization, any payments made by
     the Company in satisfaction of its obligations to Presgar and Grajo/Bleggi
     set  forth on SCHEDULE 10B (other than payments made through the issuance
     of capital stock of the Company) shall be deemed to have been made by the
     issuance of shares of the Company's common stock, regardless of the actual
     manner of payment; and (v) if the Company is able to defer the due date of
     any of the Debt set forth on SCHEDULE 10B due RGC International LTD or to
     Presgar to a date after December 31, 1998, then the amount of any such
     deferred Debt shall not be included in the determination of Total Debt
     through the sooner of the date such Debt becomes due or September 30, 1999.

          6A(4)  LIMITATION ON PRIORITY DEBT.

          (a) The Company shall not permit on, or at any time after the date
     hereof through September 30, 1998, Priority Debt to exceed 39.74% of
     Consolidated Net Worth.

          (b)  The Company and the Restricted Subsidiaries shall not incur,
     create, issue, assume, guarantee or otherwise become liable in respect of
     any Priority Debt after September 30, 1998 unless (i) no Default or Event
     of Default exists immediately before or immediately after the incurrence of
     such Priority Debt or would otherwise reasonably be anticipated to result
     therefrom; (ii) such Priority Debt is used solely to acquire fixed assets
     after September 30, 1998 and is incurred at the time of such acquisition or
     within 180 days following such date or is a renewal, refunding or
     refinancing of such Priority Debt provided the principal amount of such
     Priority Debt is not increased or the maturity thereof accelerated; (iii)
     any Lien securing such Priority Debt is confined solely to the fixed assets
     acquired with such Priority Debt, secures only the purchase price for such
     fixed assets and the Priority Debt secured thereby does not exceed the
     lesser of the fair market value or the purchase price of such fixed assets;
     (iv) the aggregate amount of Priority Debt of the Company and its
     Restricted Subsidiaries incurred after June 30, 1998 does not exceed
     $10,000,000 and (v) immediately after giving effect to the incurrence of
     such Debt on a pro forma basis, Priority Debt does not exceed the
     applicable percentage set forth below of Consolidated Net Worth determined
     as of the most recent fiscal quarter end:

<TABLE>
<CAPTION>
-------------------------------------------------------------------- 
        DATE DEBT IS INCURRED          PERCENTAGE OF CONSOLIDATED
-------------------------------------           NET WORTH
                                       ---------------------------
-------------------------------------------------------------------- 
<S>                                    <C>
 On or after September 30, 1998 but                          39.74%
 prior to December 31, 1998
-------------------------------------------------------------------- 
 On or after December 31, 1998 but                           36.25%
 prior to March 31, 1999
-------------------------------------------------------------------- 
 On or after March 30, 1999 but                              33.81%
 prior to June 30, 1999
-------------------------------------------------------------------- 
 On or after June 30, 1999 but prior                         31.35%
 to September 30, 1999
-------------------------------------------------------------------- 
 On or after September 30, 1999 but                          28.91%
 prior to December 31, 1999
-------------------------------------------------------------------- 
</TABLE> 

<PAGE>
 
                                      -5-

      <TABLE>                                                             
      <S>                                                          <C>    
      -------------------------------------------------------------------- 
       On or after December 31, 1999 but                           26.57% 
       prior to March 31, 2000                                            
      -------------------------------------------------------------------- 
       On or after March 31, 2000                                  24.51% 
      but prior to June 30, 2000                                          
      -------------------------------------------------------------------- 
       On or after June 30, 2000 but prior                         22.54% 
       to September 30, 2002                                             
      -------------------------------------------------------------------- 
       On or after September 30, 2002                              20.00% 
      -------------------------------------------------------------------- 
      </TABLE>                                                             


          For the purposes of this PARAGRAPH 6A(4):  (i) the outstanding Debt of
     any Person which becomes a Restricted Subsidiary after June 30, 1998 shall
     be deemed to have been incurred at the time it becomes a Restricted
     Subsidiary; (ii) if any outstanding Debt of the Company owned by a
     Restricted Subsidiary or any outstanding Debt of a Restricted Subsidiary
     owned by the Company or another Restricted Subsidiary is sold or otherwise
     transferred to a Person who is not the Company or a Restricted Subsidiary,
     such Debt shall be deemed to have been incurred on the date of such sale or
     transfer; (iii) any Debt which is extended, renewed, refunded, refinanced
     after the Closing Date shall be deemed incurred on the date of such
     extension, renewal, refunding or refinancing; and (iv) in making any
     determination of Consolidated Total Capitalization, any payments made by
     the Company in satisfaction of its obligations to Presgar and Grajo/Bleggi
     set  forth on SCHEDULE 10B (other than payments made through the issuance
     of capital stock of the Company) shall be deemed to have been made by the
     issuance of shares of the Company's common stock, regardless of the actual
     manner of payment.

          (c)  Notwithstanding the foregoing, if prior to December 31, 1999 the
     Company has obtained and thereafter maintains a ratio of (a) Consolidated
     EBITA to (b) Consolidated Interest Expense, for the four most recently
     ended fiscal quarters taken as a single accounting period, of not less than
     2.50 to 1.00; and after incurrence thereof, Priority Debt does not exceed
     20% of Consolidated Net Worth as at the most recent fiscal quarter end, the
     Restricted Subsidiaries may incur up to $5,000,000 in the aggregate of
     Priority Debt in addition to that permitted under SUBPARAGRAPH (A) of this
     PARAGRAPH 6A(4)  provided: (a) no Default or Event of Default exists
                      --------                                           
     immediately before or immediately after the incurrence of such additional
     Priority Debt or would otherwise reasonably be anticipated to result
     therefrom; (b) such Priority Debt is used solely for working capital
     purposes; (c) any Lien securing such Priority Debt is solely on assets
     acquired by such Restricted Subsidiary after December 31, 1999; and (d)
     such Priority Debt is not directly or indirectly Guaranteed by the
     Company."

     (4) Capital Expenditures.  The following paragraph 6A(5) is added:
         --------------------                                          

          "6A(5)  CAPITAL EXPENDITURES.  The Company will not incur aggregate
     capital expenditures in excess of $4,000,000 during the period July 1, 1998
     through December 31, 1998."

     (5) Additional Covenants.  The following paragraph 6E is added to the Note
         --------------------                                                  
Agreements:

          "6E.  ADDITIONAL COVENANTS
<PAGE>
 
                                      -6-

          6E(1).  EQUITY RELATED PAYMENTS.  The Company will not after July 31,
     1998, whether in connection with the issuance of Equity Interests in
     consideration for an Acquisition, for the raising of capital or otherwise,
     enter into or become obligated in respect of any price protection
     agreements, repurchase or redemption obligations, or any penalty payments
     in respect of any Equity Interests as a result of a failure of the Company
     to register (or to timely register) such Equity Interests under the
     Securities Act or any other similar obligations, in each case,  which are
     or might be payable in cash.   The Company will not after July 31, 1998
     enter into any amendment of the Repurchase Obligations or the Contingent
     Obligations which would increase the aggregate amounts due thereunder which
     are, or might be required to be, paid in cash.

          6E(2).  USE OF PROCEEDS OF SALES OF UNRESTRICTED SUBSIDIARIES.  The
     Company will, after payment of usual and customary transaction costs and
     expenses and repayment of obligations of StarMed Staffing, Inc. required by
     the terms of the Stock Purchase Agreement among the Company, RehabCare
     Group, Inc. and Healthcare Staffing Solutions, Inc. dated as of July 8,
     1998 (the "Stock Purchase Agreement") use the amounts received (or to be
                ------------------------                                     
     received) by the Company thereunder only to pay those obligations set forth
     on SCHEDULE 6E(2) and for working capital purposes."

          6E(3).  UPDATING OF REPRESENTATIONS AND WARRANTIES.  On or before
     November 15, 1998, the Company will provide each Holder with an Officers'
     Certificate to the effect that, subject to the disclosure schedules
     attached to the June Note Agreement and the updated disclosure schedules
     attached to such Officers' Certificate, each of the representations and
     warranties set forth in paragraph 8B, 8D, 8E, 8G, 8H, 8K, 8M, 8N, 8O, 8Q
     and 8S of the Note Agreements are true and correct in all material respects
     on and as if made as of the date thereof.
 
     (6)  Definitions.
          ----------- 

          (a)  The following definitions to the Note Agreements are amended and
     restated as follows:

          "CONSOLIDATED EBITA" means for any period the amount of which is to be
     determined, Consolidated Net Income for such period plus (but only to the
     extent such amounts were included in the computation of Consolidated Net
     Income and without duplication) (i) Consolidated Interest Expense, (ii)
     income tax expense (including deferred income tax expense in each case),
     (iii) amortization expense of the Company and its Restricted Subsidiaries
     for such period, (iv) minority interest, (v) the aggregate amount of
     charges associated with (A) ongoing expenses and/or charges related to
     litigation commenced against the Company prior to January 1, 1998, but
     excluding such expenses paid in cash after the date hereof in excess of
     $1,000,000, in the aggregate (to the extent of such excess) (reduced by any
     insurance proceeds paid to the Company in respect of such expenses), (B)
     closings or dispositions, publicly announced prior to August 1, 1998, of
     Company facilities, but excluding expenses paid in cash in excess of
     $1,500,000 in the aggregate, to the extent of such excess, (C) aggregate
     penalty payments not exceeding $2,520,000 (exclusive of interest) incurred
     as a result of the failure of  the Company to timely fulfill its
     registration obligations with respect to the shares of the Company's common
     stock into which the Company's preferred stock issued to RGC International
     LTD is convertible, as set forth on SCHEDULE 10B; (D) stock option-based
     compensation relating to employee stock options granted on or before
     December 31, 1997 and (E) charges associated with the issuance of the
     Warrants, less (but only to the extent included in the 
<PAGE>
 
                                      -7-

     computation of Consolidated Net Income) any gain recognized by the Company
     associated with the sale of stock of certain of its Unrestricted
     Subsidiaries pursuant to the Stock Purchase Agreement, such amounts being
     determined in each case on a consolidated basis in accordance with GAAP.

          "RESTRICTED PAYMENTS" means the declaration, payment or making,
     directly or indirectly, of any dividend, payment or other distribution on
     or in respect of any Equity Interest of the Company or any Restricted
     Subsidiary (other than the payment of a dividend, payment or other
     distribution to the Company or Wholly-Owned Restricted Subsidiary or the
     setting apart of any funds or property therefor, or the making of any
     payment on account of the purchase, redemption, retirement or other
     acquisition, direct or indirect, of any Equity Interest of the Company or
     any Restricted Subsidiary (other than any such Equity Interest owned by the
     Company or a Wholly-Owned Restricted Subsidiary) including without
     limitation, (x) the forgiveness or foreclosure by the issuer of any Debt
     secured by a pledge of such capital stock, (y) any purchase, redemption or
     other acquisition or retirement for value prior to any scheduled maturity,
     any scheduled prepayment of principal or any scheduled sinking fund payment
     or, in any event, during the continuance of any Default, or Event of
     Default of any Debt that is subordinated in right of payment to the Notes
     and  (z) cash payments after June 30, 1998 in excess of $1,000,000 in the
     aggregate (net of any insurance proceeds paid to the Company in respect
     thereof) in respect of shareholder litigation.  The Repurchase Obligations
     shall not constitute Restricted Payments

          (b)  The following definitions are added to the Note Agreements in the
     appropriate alphabetical order:

          "CONTINGENT OBLIGATIONS"  means any and all obligations of the Company
     or a Restricted Subsidiary, other than the Repurchase Obligations, which
     pursuant to the terms of such obligations may be or could have been
     satisfied by the Company or such Restricted Subsidiary by the issuance of
     Equity Interests (even if such ability was conditioned upon the Company
     having in effect a registration statement for such Equity Interest or such
     Equity Interest having a minimum trading price) and (but without
     duplication) the aggregate amount of cash paid by the Company or a
     Restricted Subsidiary after July 31, 1998 to any Person in respect of a
     penalty for failing to have a registration statement under the Securities
     Act in effect for the benefit of such Person.

          "REPURCHASE OBLIGATIONS"  means the obligations of the Company to
     Capstone, Novick/Rossi and O'Connor/San Jose and set forth on SCHEDULE 10B
     to repurchase or redeem shares of its Common Stock issued  in connection
     with Acquisitions, whether or not now represented by a promissory note, up
     to an aggregate amount of $9,500,000, inclusive of any interest, premium or
     penalties due in connection therewith.

          "WARRANTS"  means the Warrants for an aggregate of 375,000 shares of
     the Company's common stock, $.01 par value per share issued to the
     Purchasers on September 23, 1998.

     (7) Exhibits.  SCHEDULE 10B in the form of EXHIBIT A to this Agreement is
         --------                                                             
added to the Note Agreement.
 
     3.   REPRESENTATIONS AND WARRANTIES.
<PAGE>
 
                                      -8-

     (1)  Subject to the disclosure schedules attached to the June Note
Agreement, each of the representations and warranties set forth in paragraphs 8A
and 8F of the Note Agreements are true and correct in all material respects on
and as if made as of the date hereof and after giving effect to the transactions
contemplated by this Agreement.

     (2) Except for the Contingent Obligations and the Repurchase Obligations
(as such terms are defined in Section 2 (6)) set forth on Exhibit A, the Company
                                                         ----------             
does not have any repurchase or redemption obligations, price protection
obligations or penalty obligations relating to any Equity Interests or any
obligation to register any Equity Interests.  Exhibit A accurately sets forth
                                              ---------                      
the financial obligations of the Company in respect of its Contingent
Obligations and Repurchase Obligations as of the date hereof.

     (3) Since June 30, 1998, neither the Company nor any of the Restricted
Subsidiaries has incurred any Debt.

     (4) The Company has furnished the Purchasers with the audited balance sheet
of the Consolidated Group dated as of December 31, 1997 and the related
statements of operations, cash flows and stockholders' equity for the 12 months
ended on such date and the unaudited balance sheet of the Company as of June 30,
1998 and the related statement of operations, cash flows and stockholders'
equity for the six months ended on such date.  The audited financial statements
fairly present in all material respects the financial condition of the
Consolidated Group and the results of its operations and cash flows for the
respective periods specified thereby and the unaudited financial statements
fairly present in all material respects the assets and liabilities of the
Company as of the date thereof.  The financial statements have been prepared in
accordance with GAAP, consistently applied throughout the periods involved
except as set forth in the notes thereto.  Since June 30, 1998, there have been
no developments or changes affecting the business, assets, liabilities,
condition (financial or otherwise) of the Company or any Restricted Subsidiary
which has had or is reasonably expected to have, either individually or in the
aggregate, a Material Adverse Effect.

     (5) As of the date hereof, the Company has no direct or indirect equity or
beneficial ownership in any Unrestricted Subsidiary.

     4.  DELIVERIES.  Concurrently with the execution and delivery of this
Agreement by the Company, the Company shall deliver to the Purchasers:

     (1) Principal Prepayment  By wire transfer of immediately available funds
         --------------------                                                 
in accordance with the instructions set forth on Exhibit A to the Note
Agreements, a prepayment of principal of the Notes, without Make Whole Amount,
in the aggregate  amount of $2,000,000.  Such prepayment of principal is to be
allocated among the Purchasers in proportion to the aggregate principal amount
of the Notes held by each.  Each Purchaser agrees to apply such prepayment of
principal to the scheduled payment of principal due on February 20, 2001.  The
parties hereto acknowledge that such payment is to be made from the Escrow Funds
(as such term is defined in the Escrow Agreement, dated as of August 14, 1998,
by and between the Company, IBJ Schroder Bank & Trust Company, as Escrow Agent
(the "Escrow Agent"), and the Purchasers (the "Escrow Agreement").  The Company
      ------------                             ----------------                
and the Purchasers shall provide the Escrow Agent with joint written
instructions in the form of Exhibit B hereto in order to effect such payment.

     (2) Restructuring Fee.   By wire transfer of immediately available funds in
         -----------------                                                      
accordance with the instructions set forth on Exhibit A to the Note Agreements,
a restructuring fee in the 
<PAGE>
 
                                      -9-

aggregate amount of $500,000. Such restructuring fee is to be allocated among
the Purchasers in proportion to the aggregate principal amount of the Notes held
by each.

     (3) Warrants.  Warrants in the form attached as EXHIBIT C  for an aggregate
         --------                                    ---------                  
of 375,000 shares of the Company's common stock, $.10 par value per share.  Such
Warrants are to be allocated among the Purchasers in proportion to the aggregate
principal amount of the Notes held by each. Each Purchaser's Warrants shall be
registered in such Purchaser's name or the name of its nominee as specified in
Exhibit A to the Note Agreements.

     (4) Registration Rights Agreement.  An executed Registration Rights
         -----------------------------                                  
Agreement in the form of EXHIBIT D.
                         --------- 

     (5) Allonges to Notes.  An executed allonge to such Purchaser's Note(s) in
         -----------------                                                     
the form of EXHIBIT E.
            --------- 

     (6) Opinion of Counsel. An opinion of Wilkie, Farr & Gallagher as to (i)
         ------------------                                                  
the legal existence and corporate power and authority of the Company, (ii) the
due authorization, execution, delivery and enforceability of this Agreement, the
Warrants, the Registration Rights Agreement and the Allonges, (iii) the absence
of conflicts with or creation of liens under applicable law in connection
therewith and (iv) the absence of any required governmental consents in
connection therewith, in form and substance satisfactory to the Purchasers.

     (7) Payment of Expenses.  All Expenses, including those of Special Counsel,
         -------------------                                                    
as set forth in invoices delivered to the Company prior to the date hereof shall
have been paid in full.

     (8) Interest Payment.  Except to the extent previously paid, by wire
         ----------------                                                
transfer of immediately available funds in accordance with the instructions set
forth on Exhibit A to the Note Agreements, interest accrued on each Note from
February 20, 1998 through August 20, 1998 reflecting the increase in interest
rate provided for in Section 2(1) and the accrued monthly interest on the Notes
due September 20, 1998.

     (9) Warrant Valuation.  The amendments to the financial covenants set forth
         -----------------                                                      
in Section 2(4) of this Agreement have been agreed to on the express
understanding that the value of the Warrants as of the date of issuance will be
$500,000.  If the value of the Warrants on such date is materially different
from $500,000, the parties agree that the financial covenants set forth in 2(4)
of this Agreement will be appropriately adjusted to reflect the actual valuation
of the Warrants on such date.
 
     5.   NO OTHER WAIVERS.  Except as expressly set forth herein or as
previously amended, the Note Agreements shall continue in full force and effect
without alteration or amendment and except as expressly set forth herein no
other waiver of any Default or Event of Default is hereby granted.

     6.   GOVERNING LAW.  THIS AGREEMENT IS TO BE CONSTRUED AND ENFORCED IN
ACCORDANCE WITH, AND THE RIGHTS OF THE PARTIES SHALL BE GOVERNED BY, THE LAWS OF
THE STATE OF NEW YORK (WITHOUT GIVING EFFECT TO ANY LAWS OR RULES RELATING TO
CONFLICTS OF LAWS THAT WOULD CAUSE THE APPLICATION OF THE LAWS OF ANY
JURISDICTION OTHER THAN THE STATE OF NEW YORK).
<PAGE>
 
                                      -10-

     7.   COUNTERPARTS.  This Agreement may be executed simultaneously in two or
more counterparts, each of which shall be deemed an original, and it shall not
be necessary in making proof of this Agreement to produce or account for more
than one such counterpart.

     This Agreement is executed under seal as of the date first above written.
 
                                       MEDICAL RESOURCES, INC.                
                                                                                
                                       By: /s/ Christopher J. Joyce
                                          ---------------------------------
                                           Title: Senior Vice President - Legal
                                                  Affairs and Administration
                                                                              
                                       Purchasers under the February          
                                       Note Agreement:                        
                                                                              
                                       JOHN HANCOCK MUTUAL LIFE               
                                       INSURANCE COMPANY                      
                                                                              
                                       By: /s/ Stephen J. Blewitt
                                          ---------------------------------
                                            Name: Stephen J. Blewitt
                                            Title:  Senior Investment Officer
                                                                              
                                       JOHN HANCOCK VARIABLE LIFE             
                                       INSURANCE COMPANY                      
                                                                              
                                       By: /s/ Stephen J. Blewitt
                                          ---------------------------------
                                            Name: Stephen J. Blewitt
                                            Title:  Senior Investment Officer

                                       INVESTORS PARTNER LIFE INSURANCE       
                                       COMPANY                                
                                                                              
                                       By: /s/ Stephen J. Blewitt
                                          ---------------------------------
                                            Name: Stephen J. Blewitt
                                            Title:  Senior Investment Officer

                                       Mellon Bank, N.A., solely in its capacity
                                       as Trustee for The Long Term Investment
                                       Trust, (as directed by John Hancock
                                       Mutual Life Insurance Company), and not
                                       in its individual capacity

                                       By: /s/ Bernadette Rist
                                          ---------------------------------
                                            Name: Bernadette Rist
                                            Title: Authorized Signatory
                                                                              
                                                                              
                                       AUSA LIFE INSURANCE COMPANY, INC.      
                                                                              
                                       By: /s/ Gregory W. Theobald
                                          ---------------------------------
                                            Name: Gregory W. Theobald
                                            Title: V.P. and Asst. Secretary
<PAGE>
 
                                      -11-

                                       LIFE INVESTORS INSURANCE COMPANY         
                                       OF AMERICA                               
                                                                                
                                       By: /s/ Gregory W. Theobald
                                           ------------------------------
                                            Name: Gregory W. Theobald
                                            Title: V.P. and Asst. Secretary
                                                                                
                                       GREAT AMERICAN LIFE INSURANCE            
                                       COMPANY                                  
                                                                                
                                       By: /s/ Mark F. Muething
                                           ------------------------------
                                            Name: Mark F. Muething
                                            Title: Senior Vice President
                                                                                
                                       GREAT NORTHERN INSURED ANNUITY           
                                       CORPORATION                              
                                                                                
                                       By: /s/ Jon M. Lucia
                                           ------------------------------
                                            Name: Jon M. Lucia
                                            Title: Vice President
                                                                                
                                       AMERICAN BANKERS INSURANCE COMPANY       
                                       OF FLORIDA                               
                                                                                
                                       By: /s/ Robert L. Kisiel
                                           ------------------------------
                                            Name: Robert L. Kisiel
                                            Title: Director of Investments
                                                                                
                                       COVA FINANCIAL SERVICES LIFE INSURANCE   
                                       COMPANY                                  
                                                                                
                                       By:  CONNING ASSET MANAGEMENT            
                                             COMPANY                            
                                                                                
                                       By: /s/ Laura R. Caro
                                           ------------------------------
                                            Name: Laura R. Caro
                                            Title: Senior Vice President
                                                                                
                                       HARE & CO. (with respect to Senior Note
                                       N12 as nominee of Lincoln National Life
                                       Insurance Company)
                                       
                                       By: /s/ Donna Steineman
                                           ------------------------------
                                            Name: Donna Steineman
                                            Title: Asst. Vice President
<PAGE>
 
                                      -12-

                                       Purchasers under the June Note Agreement:
                                                                                
                                       JOHN HANCOCK MUTUAL LIFE                 
                                       INSURANCE COMPANY                        
                                                                                
                                       By: /s/ Stephen J. Blewitt
                                           ------------------------------
                                            Name: Stephen J. Blewitt
                                            Title: Senior Investment Officer
                                                                                
                                       JOHN HANCOCK VARIABLE LIFE               
                                       INSURANCE COMPANY                        
                                                                                
                                       By: /s/ Stephen J. Blewitt
                                           ------------------------------
                                            Name: Stephen J. Blewitt
                                            Title: Senior Investment Officer
                                                                                
                                       GREAT NORTHERN INSURED ANNUITY           
                                       CORPORATION                              
                                                                                
                                       By: /s/ Jon M. Lucia
                                           ------------------------------
                                            Name: Jon M. Lucia
                                            Title: Vice President
                                                                                
                                                                                
                                                                                
                                       OCCIDENTAL LIFE INSURANCE                
                                       COMPANY OF NORTH CAROLINA                
                                                                                
                                       By:  CONNING ASSET MANAGEMENT            
                                                                                
                                       By: /s/ Laura R. Caro
                                           ------------------------------
                                            Name: Laura R. Caro
                                            Title: Senior Vice President
                                                                                
                                       PENINSULAR LIFE INSURANCE CO.            
                                                                                
                                       By:  CONNING ASSET MANAGEMENT            
                                                                                
                                       By: /s/ Laura R. Caro
                                           ------------------------------
                                            Name: Laura R. Caro
                                            Title: Senior Vice President
                                                                                
                                       EXECUTIVE RISK INDEMNITY INC.            
                                                                                
                                       By: /s/ Laura R. Caro
                                           ------------------------------
                                            Name: Laura R. Caro
                                            Title: Senior Vice President