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                                THIRD AMENDMENT
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                                      AND
                                      ---
                               WAIVER AGREEMENT
                               ----------------
                                        
     THIRD AMENDMENT AND WAIVER AGREEMENT (this "WAIVER AGREEMENT") dated as of
April 14, 1997 by and among Moore Medical Corp. (the "BORROWER"), Bank of Boston
Connecticut and certain other lending institutions (collectively, the "BANKS"),
and Bank of Boston Connecticut, as agent for the Banks (in such capacity, the
"AGENT"), amending a certain Revolving Credit Agreement dated as of January 9,
1996, as amended by the First Amendment Agreement dated as of March 1, 1996 and
the Second Amendment Agreement dated December 27, 1996 (as amended, the "CREDIT
AGREEMENT").

                                  WITNESSETH
                                  ----------
                                        
     WHEREAS, the Borrower has requested that the Banks amend certain terms and
conditions of the Credit Agreement and waive certain Events of Default which
exist under the Credit Agreement; and

     WHEREAS, the Banks are willing to amend such terms and conditions and waive
such Events of Default on the terms and conditions set forth herein.

     NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties hereto agree as
follows:

     S1.  DEFINITIONS.  Capitalized terms used herein without definition that
          -----------                                                        
are defined in the Credit Agreement shall have the same meanings herein as
therein.

     S2.  RATIFICATION OF EXISTING AGREEMENTS.  All of the Borrower's
          -----------------------------------                        
obligations and liabilities to the Agent and the Banks, and all the Agent's and
Banks' obligations and liabilities to the Borrower, as evidenced by or otherwise
arising under the Credit Agreement, the Notes and the other Loan Documents,
except as otherwise expressly modified in this Waiver Agreement upon the terms
set forth herein, are, by the Borrower's, the Agent's and Banks', execution of
this Waiver Agreement ratified and confirmed in all respects.  In addition, by
the Borrower's execution of this Waiver Agreement, the Borrower represents and
warrants that, subject to the provided and provided, however, clauses of Section
                              --------     --------  -------                    
5.4 of the Credit Agreement, no counterclaim, right of set-off or defense of any
kind exists or is outstanding with respect to such obligations and liabilities.

     S3.  REPRESENTATIONS AND WARRANTIES.  All of the representations and
          ------------------------------                                 
warranties made by the Borrower in the Credit Agreement, the Notes and the other
Loan Documents are true and correct on the date hereof as if made on and as of
the date hereof, except for the Events of Default described in S5 hereof and
except to the extent that any of such representations and warranties relate by
their terms to a prior 

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date and except to the extent of changes resulting from transactions
contemplated or permitted by the Credit Agreement and changes occurring in the
ordinary course of business that singly or in the aggregate do not have a
Material Adverse Effect.

     S4.  CONDITIONS PRECEDENT.  The effectiveness of the amendments and waivers
          --------------------                                                  
contemplated hereby shall be subject to the satisfaction on or before the date
hereof of each of the following conditions precedent:

          (a)  Representations and Warranties.  All of the representations and
               ------------------------------                                 
warranties made by the Borrower herein, whether directly or incorporated by
reference, shall be true and correct on the date hereof, except as provided in
S3 hereof.

          (b)  Performance; No Event of Default.  The Borrower shall have
               --------------------------------                          
performed and complied in all material respects with all terms and conditions
herein required to be performed or complied with by it prior to or at the time
hereof, and there shall exist no Default or Event of Default except for the
Events of Default described in S5 hereof.

          (c)  Corporate Action.  All requisite corporate action necessary for
               ----------------                                               
the valid execution, delivery and performance by the Borrower of this Waiver
Agreement and all other instruments and documents delivered by the Borrower in
connection therewith shall have been duly and effectively taken.

          (d)  Delivery.  The parties hereto shall have executed and delivered
               --------                                                       
this Waiver Agreement.  In addition, the Borrower shall have executed and
delivered such further instruments, and take such further action as the Agent
and the Banks may have reasonably requested, in each case further to effect the
proposes of this Waiver Agreement, the Credit Agreement and the other Loan
Documents.

          (e)  Fees and Expenses.  The Borrower shall have paid to the Agent and
               -----------------                                                
the Banks all fees and expenses incurred by the Agent in connection with this
Waiver Agreement, the Credit Agreement or the other Loan Documents on or prior
to the date hereof.

     S5.  WAIVERS.  Subject to the satisfaction of the conditions set forth
          -------                                                          
below, the Banks waive those Events of Default that have occurred under the
Credit Agreement as a result of the Borrower's failure on or before March 29,
1997 to comply with those sections of the Credit Agreement set forth on 
Schedule 1 attached hereto. The waiver set forth in this S5 shall be effective
----------
only for those Events of Defaults contained in the Credit Agreement as specified
in the preceding sentence occurring on or before March 29, 1997 and such waiver
shall not entitle the Borrower to any future waiver in similar or other
circumstances. Without limiting the foregoing, upon the occurrence of an Event
of Default after March 29, 1997, or if an Event of Default has occurred and is
continuing on the date hereof that is not set forth on Schedule 1, the Banks
                                                       ----------
shall be free in their sole and absolute discretion to accelerate the payment in
full of the Borrower's

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indebtedness to the Agent and the Banks under the Loan Agreement and the other
Loan Documents, and may, if the Banks so elect, proceed to enforce any or all of
the Agent's and the Bank's rights under or in respect of the Credit Agreement,
the Notes and the other Loan Documents and applicable law.

     S6.  AMENDMENTS TO SS10.1 AND 10.2.  Sections 10.1 and 10.2 of the Credit
          ------------------------------                                      
Agreement are hereby amended in their entirety to read as follows:

          "S10.1.  Earnings Before Interest and Taxes to Total Interest Expense.
                   ------------------------------------------------------------
The Borrower will not permit the ratio of Earnings Before Interest and Taxes to
Consolidated Total Interest Expense to be less than 1.5:1.0 for (i) the period
of two consecutive fiscal quarters of the Borrower ending on June 28, 1997, (ii)
the period of three consecutive fiscal quarters of the Borrower ending on
September 27, 1997 and (iii) any period of four consecutive fiscal quarters of
the Borrower ending on or after January 3, 1998."

          "S10.2.  Cash Flow to Financial Obligations.  The Borrower will not
                   ----------------------------------                        
permit the ratio of Consolidated Operating Cash Flow to Consolidated Financial
Obligations to be less than 1.25:1.0 for (i) the period of two consecutive
fiscal quarters of the Borrower ending on June 28, 1997, (ii) the period of
three consecutive fiscal quarters of the Borrower ending on September 27, 1997,
(iii) any period of four consecutive fiscal quarters of the Borrower ending on
or after January 3, 1998."

     S7.  EXPENSES.  The Borrower agrees to pay to the Agent upon demand an
          --------                                                         
amount equal to any and all out-of-pocket costs or expenses (including
reasonable legal fees and disbursements and appraisal expenses) incurred or
sustained by the Agent in connection with the preparation of this Waiver
Agreement and any related matters.

     S8.  MISCELLANEOUS.
          -------------

          (a)  This Waiver Agreement shall be governed by and construed in
accordance with the laws of the State of Connecticut.

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          (b) Except as otherwise expressly provided by this Waiver Agreement,
all of the respective terms, conditions and provisions of the Credit Agreement
shall remain the same and in full force and effect.  It is declared and agreed
by each of the parties hereto that this Waiver Agreement and the Credit
Agreement be read and construed as one instrument, and all referenced in the
Loan Documents to the Credit Agreement shall hereafter refer to the Credit
Agreement, as amended by this Waiver Agreement.

     IN WITNESS WHEREOF, each of the parties hereto have caused this Waiver
Agreement to be executed in its name and behalf by its duly authorized officer
as of the date first written above.

                                    MOORE MEDICAL CORP.


                                    By: /s/ John A. Murray
                                        ------------------
                                        Title: Vice President

 
                                    BANK OF BOSTON CONNECTICUT,
                                    Individually and as Agent


                                    By: /s/ Donald W. Peters
                                        --------------------
                                        Title: Vice President
 
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                                  SCHEDULE 1
                                  ----------

             Existing Events of Default under the Credit Agreement
             -----------------------------------------------------

     Failure to comply with SS10.1, 10.2 and 10.4 of the Credit Agreement as of
December 28, 1996 and SS10.1 and 10.2 as of March 29, 1997.
 
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