ALLONGE TO REPLACEMENT PROMISSORY NOTE

         This  Allonge  made this 4th day of August,  2000,  to the  Replacement
Promissory Note dated December 20, 1996, as amended by Allonge dated January 11,
1999 and Allonge dated August 20, 1999, made by The Bank of New York, not in its
individual or corporate  capacity,  but solely in its capacity as Trustee of the
Mid Atlantic Medical Services,  Inc. Stock  Compensation  Trust  ("Borrower") in
favor of Mid Atlantic Medical Services, Inc. ("Lender").

         WHEREAS,  Borrower  executed  and  delivered  to  Lender a  Replacement
Promissory  Note dated  December  20, 1996 in the original  principal  amount of
$129,902,500 (the "Original Note").

         WHEREAS,  the Original Note was most recently  amended by an Allonge on
August 20, 1999.

         WHEREAS,  under the terms of such Allonge,  the principal amount of the
Original   Note  due  and  owing  as  of  August  20,  1999  was   increased  to
$127,284,696.75.

         WHEREAS,  $117,084,696.75 of the principal amount of the Original Note,
as amended by such Allonge (the "Amended  Note")  remains  unpaid as of the date
hereof.

         WHEREAS,  in order to finance  the  Borrower's  purchase  of  2,000,000
shares of the  Lender's  common  stock  pursuant  to the  terms of Common  Stock
Purchase  Agreement  of even date  herewith  between  the  Borrower  and Lender,
Borrower  and Lender wish to increase the  principal  amount of the Amended Note
due and owing from  $117,084,696.75 to  $145,814,696.75  while leaving all other
terms of the Amended Note unamended.

         NOW, THEREFORE, for good and valuable consideration and intending to be
legally bound hereby, the parties hereto agree as follows:

                  (1) The  Amended  Note  is  hereby  amended  by  deleting  all
         references  to  "$127,284,696.75"  and by  inserting  in  lieu  thereof
         "$145,814,696.75."

                  (2) The last  sentence of the second  paragraph of the Amended
         Note is hereby  amended by deleting  the date  "August 20, 1999" and by
         inserting in lieu thereof "August 4, 2000."

                  (3) Schedule A attached to the Amended Note is hereby  amended
         and restated in its entirety in the form attached hereto as Exhibit 1.

                  (4) Schedule B attached to the Amended Note is hereby  amended
         and restated in its entirety in the form attached hereto as Exhibit 2.

                  (5)      Except as expressly amended hereby, the Amended Note
         shall remain unamended and in full force and effect.



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         IN WITNESS  WHEREOF,  this Allonge to  Replacement  Promissory  is made
effective as of the 4th day of August, 2000.

Attest:                            THE BANK OF NEW YORK, not in its individual
                              corporate capacity, but solely in its capacity as
                              Trustee of the Mid Atlantic Medical Services, Inc.
                              Stock Compensation Trust
/S/Paulette S. Bagil, AT              /S/ Richard J. Barry
____________________________      By:_______________________________________
                                          Vice President
                                   Title:_____________________________________


Attest:                               MID ATLANTIC MEDICAL SERVICES, INC.
                                        /S/ Robert E. Foss
______________________________      By:_______________________________________
                                          Sr. EVP & CFO
                                   Title:_____________________________________

Source: OneCLE Business Contracts.