Page 57
                                                             Exhibit 10(iii)A(4)


                                 AMENDMENT NO. 3
                                       TO
                        NATIONAL SERVICE INDUSTRIES, INC.
                            BENEFITS PROTECTION TRUST



         This  Amendment  made and  entered  into as of this 6th day of January,
1999, by and between National Service Industries,  Inc., a Delaware  Corporation
(the  "Company"),  and Wachovia  Bank,  N.A.  (formerly  Wachovia Bank and Trust
Company), as Trustee (the "Trustee");


                     W - I - T - N - E - S - S - E - T - H:


         WHEREAS,  the Company previously  established a trust arrangement known
as the National Service Industries, Inc. Benefits Protection Trust (the "Trust")
in order to ensure  that,  in the event of Change  in  Control  of the  Company,
designated  participants and their beneficiaries  receive the benefits which the
Company  and its  Affiliates  are  obligated  to  provide  pursuant  to  various
executive compensation arrangements (collectively, the "Plans"); and

         WHEREAS,  the  Company  now  desires  to amend the Trust in a number of
respects;

         NOW, THEREFORE, for and in consideration of the premises and the mutual
covenants contained herein, the parties hereto agree as follows:

                                       1.

         Section 3.4 is hereby  amended by deleting the present provision in its
entirety  and  substituting  the  following in lieu thereof:

                  "3.4 Upon the occurrence of a Threatened  Change in Control or
         a Change in  Control,  the  Company  shall  contribute  to the  Trustee
         Expense  Account  sufficient cash (i) to provide for the Litigation (as
         defined in Section  9.3 of Article 9)  expenses  of all  Plaintiffs  as
         determined  by the  Trustee,  and (ii) to pay the expenses of operating
         this Trust for twelve (12) months.  If the Company fails to deposit the
         amount in the Trust  required by this  Section 3.4 within five (5) days
         of the  occurrence  of a  Threatened  Change in  Control or a Change in
         Control, the Trustee shall commence legal action as provided in Section
         9.5."

                                       2.

         Section 4.2 is hereby amended by designating the first paragraph of the
present  section as  subparagraph  (a), by deleting the second  paragraph of the
present  section in its entirety,  and by adding the following new  subparagraph
(b) in Section 4.2:

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                                                             Exhibit 10(iii)A(4)

                  "(b) Immediately upon the occurrence of a Threatened Change in
         Control or a Change in Control, the Company shall contribute sufficient
         cash to the Benefit  Account (i) to pay all  payments  and  benefits to
         which Participants would be entitled (whether payable currently or on a
         deferred  basis)  pursuant  to the terms of the Plans as of the date of
         the  Threatened  Change in Control or Change in Control and (ii) to pay
         the  additional  payments and benefits  that would be due  Participants
         under the Plans  assuming the  Participants'  employment was terminated
         involuntarily  by the Company without cause  immediately  following the
         date on which the  Threatened  Change in  Control  or Change in Control
         occurred. The amount the Company shall contribute to the Trust pursuant
         to this  subparagraph  (b) shall be  determined  by the  Trustee in its
         discretion.  If the Company fails to contribute the amount to the Trust
         required  by  this  subparagraph  (b)  within  five  (5)  days  of  the
         occurrence  of the  Threatened  Change in Control or Change in Control,
         the Trustee shall commence legal action as provided in Section 9.5.

                           During a Threatened Change in Control Period or after
         the occurrence of a Change in Control,  if the Trustee  determines that
         the funds in the  Benefit  Account  are  insufficient  to fully pay all
         payments  and  benefits in (b)(i) and (ii) above  under the Plans,  the
         Trustee shall make written demand on the Company to provide funds in an
         amount  determined  by the  Trustee in its  discretion.  If the Company
         fails to contribute this additional amount to the Trust within five (5)
         days of receipt of the  Trustee's  written  demand,  the Trustee  shall
         commence legal action as provided in Section 9.5."

                                       3.

         Section  4.3 is hereby  amended by deleting  the present section in its
entirety  and  substituting  the  following  in lieu thereof:

                  "4.3(a)  In  addition  to  the  cash  and/or  other   property
         delivered to, and deposited with, the Trustee pursuant to Article 3 and
         Sections  4.1 and 4.2,  the  Company  may deliver to the Trustee one or
         more letters of credit  (referred to  hereinafter  as the "Letter(s) of
         Credit")  which shall (i) be  irrevocable  for a period of at least 364
         days, (ii) be renewable by the Company on substantially  the same terms
         and conditions at the end of such period unless the issuer  provides to
         the Company and the  Trustee  not less than 90 calendar  days'  written
         notice prior to the  expiration  date that any Letter(s) of Credit will
         not be renewed, and (iii) name the Trustee as beneficiary.  A Letter of
         Credit  shall  enable the Trustee to draw  directly  from the issuer of
         such  Letter of Credit,  immediately  upon notice and without any other
         requirement,  an amount  equal to the  excess of 100% of the amount the
         Trustee has demanded the Company  contribute  to the Trust  pursuant to
         Article 3 and Sections 4.1 and 4.2, as determined by the Trustee,  over
         the value of all other assets of the Trust,  subject,  however,  to the
         maximum amount of the Letters of Credit.

                  (b) The Trustee shall draw on each Letter of Credit held by it
         to the full  extent  thereof  no later  than  three (3)  business  days
         following  the  failure by the Company to  contribute  to the Trust the
         amounts  demanded by the Trustee pursuant to Article 3 and Sections 4.1
         and 4.2.

                                                                         Page 59
                                                             Exhibit 10(iii)A(4)


                  (c) If the  Trustee  receives  written  notice  from an issuer
         referencing  a Letter of Credit by number which is signed by an officer
         of the issuer of such Letter of Credit, that such Letter of Credit will
         not be renewed on substantially the same terms and conditions, then the
         Trustee  shall notify the Company in writing that it has received  such
         notice.

                  (d)  Notwithstanding  (a) above, the Trustee shall not draw on
         any Letter of Credit pursuant to  subparagraph  (a), to the extent that
         the Company has  deposited  in the Trust 100% of the amount the Trustee
         has demanded the Company to contribute to the Trust pursuant to Article
         3 and Sections 4.1 and 4.2, as determined by the Trustee."

                                       4.

         Article 7 is hereby amended by redesignating the current Section 7.5 as
Section 7.6 and adding the  following  new Section 7.5:

                  "7.5     To draw upon any Letter of Credit  provided  pursuant
         to  Section  4.3  and  to  make demand upon the issuer of any Letter of
         Credit to pay amounts directly to the Trust."

                                       5.

         Section  9.4 is hereby  amended by deleting  the present section in its
entirety  and  substituting  the  following  in lieu thereof:

                  "9.4 After a Change in  Control,  the  Trustee  shall bill the
         Company  directly,  on a  monthly  basis,  for all  fees  and  expenses
         described  in Section  10.2.  The Trustee  may  commence  legal  action
         against the  Company to recover any amount not paid within  thirty (30)
         days of the  billing  date.  If the  Company's  failure to pay causes a
         reduction  in the assets of the  Trustee  Expense  Account  contributed
         pursuant  to  Article  3 such  that  the  Trustee  Expense  Account  is
         insufficient to pay for all expenses that may be incurred in connection
         with the  Litigation,  the  Trustee  shall  commence  legal  action  as
         provided in Section 9.5."

                                       6.

         Section  9.5 is hereby  amended by deleting  the present section in its
entirety  and  substituting  the  following  in lieu thereof:

                  "9.5 Upon the occurrence of a Threatened  Change in Control or
         after a Change in  Control,  if the Company  fails to transfer  to, and
         deposit in, the Trust the amounts  required  by Sections  3.4,  4.2 and
         9.4, (i) within five (5) days of the demand by the Trustee, the Trustee
         shall  commence  legal action to compel the Company to pay such amounts
         to the Trust  and (ii) the  Company  shall be  required  to  contribute
         within 10 days of commencement  of such action an additional  amount to
         the Trust to pay for the costs and expenses,  including  legal fees, of
         such  action.  The Trustee  shall have the power and  authority to hire
         legal  counsel of its choice to pursue  such legal  action  against the
         Company  and the  costs of such  legal  counsel  shall be paid from the
         Trust."

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                                                             Exhibit 10(iii)A(4)
                                       7.

         Article 12 is hereby amended by adding the following new Section 12.3.

                  "12.3  Nothing in this Article 12 shall require the Company to
         indemnify  the  Trustee  with  respect  to any  Letter  of  Credit  (as
         described in Section 4.3) which the Trustee or any  affiliate may issue
         in its commercial capacity,  nor may any assets of the Trust be used to
         repay the  Trustee or any  affiliate  for  amounts  the  Trustee or any
         affiliate may pay pursuant to any Letter of Credit."

                                       8.

         Article 13 is hereby  amended by adding the  following  sentence to the
end of the present Article:

                  "The  provisions of this Article 13 shall not limit in any way
         the  obligations and  responsibilities  of the Trustee or any affiliate
         pursuant to a Letter of Credit (as  described  in Section  4.3) and the
         rights of the  Trustee to draw upon any Letter of Credit  issued by the
         Trustee  or any  affiliate  shall  be as  provided  in such  Letter  of
         Credit."

                                       9.

         Section 15.4 is hereby amended by deleting the present provision in its
entirety  and  substituting  the  following in lieu thereof:

               "15.4   Until   written   notice   is  given  to  the   contrary,
          communications to the Trustee shall be sent to it at its office at 301
          N. Main Street,  P.O. Box 3099,  Winston-Salem,  North Carolina 27150,
          Attention: Mr. John N. Smith, facsimile 336-770-4059,  copy to Mr. Joe
          Long, Trust Counsel (or such other individuals as delegated in writing
          by Messrs. Smith or Long); communications to the Company shall be sent
          to it at its office at 1420 Peachtree Street, N.E., Atlanta,  Georgia,
          Attention: David Levy, facsimile 404-853-1015,  with a copy to William
          J. Vesely, Jr., Kilpatrick Stockton LLP, facsimile 404-815-6555."

                                      10.

         Section 17.3 is hereby  amended by adding the following  after the word
"thereto" in the fourth line of the present section:

                  ", including all rights under any Letters of Credit,"

                                                                         Page 61
                                                             Exhibit 10(iii)A(4)

                                      11.

         Schedule 1  is  hereby  amended  by  substituting a revised Schedule 1,
dated January 6, 1999, which is attached hereto and made a part hereof.

                                      12.

         The within and foregoing  amendments to the Trust shall be effective as
of January 6, 1999.  Except as hereby  modified,  the Trust shall remain in full
force and effect.

         IN WITNESS WHEREOF, the parties hereto have executed this Amendment No.
3 as of the day and year first written above.

                                               NATIONAL SERVICE INDUSTRIES, INC.



                                               By/s/ James S. Balloun
                                               James S. Balloun
                                               Chairman, President and
                                               Chief Executive Officer



                                                WACHOVIA BANK N.A., AS TRUSTEE



                                                By /s/Jane B. Fisher

                                                Name: Jane B. Fisher

                                                Title: Senior Vice President





Page 62
                                                             Exhibit 10(iii)A(4)



         The undersigned Affiliates of the Corporation hereby consent to, and 
agree to be bound by, this Amendment No. 3 to the Trust.

         This the 6th day of January, 1999.

                                               NATIONAL SERVICE INDUSTRIES, INC.
                                               (Georgia)



                                               By /s/ James S. Balloun
                                               James S. Balloun, President



                                               NSI ENTERPRISES, INC.



                                               By /s/ James S. Balloun
                                               James S. Balloun, President



                                               ZEP MANUFACTURING COMPANY



                                               By /s/ Glen D. Reed
                                               Glen D. Reed, President



                                               NSI SERVICES, L.P.



                                               By /s/ James S. Balloun
                                               James S. Balloun, President