Page 39
                                                         Exhibit 10(iii)A(13)(b)



                           AMENDMENT AND ADOPTION OF
                        NATIONAL SERVICE INDUSTRIES, INC.
                            EXECUTIVE BENEFITS TRUST

     This  Agreement  made and entered into as of this ____ day of  ___________,
1996,  by and  among  National  Service  Industries,  Inc.  (the  "Corporation),
Wachovia Bank and Trust Company (the "Trustee") and the following  affiliates of
the  Corporation  - North Bros.,  Inc.,  National  Service  Industries,  Inc. of
Georgia,  NSI Enterprises,  Inc., ZEP Manufacturing  Company,  and NSI Services,
L.P.:

                              W I T N E S S E T H:

     WHEREAS, the Corporation  previously  established a trust arrangement known
as the National Service Industries,  Inc. Executive Benefits Trust (the "Trust")
in order to  ensure  that  participants  and  their  beneficiaries  receive  the
benefits  which the  Corporation  and its  affiliates  are  obligated to provide
pursuant  to various  executive  compensation  arrangements  (collectively,  the
"Plans")  and to provide  for  additional  funding of the Trust upon a Change in
Control of the Corporation; and

     WHEREAS,  effective as of August 31, 1996, the Corporation  will reorganize
its operations into several  newly-formed  subsidiary  corporations  and limited
partnerships  including North Bros., Inc., National Service Industries,  Inc. of
Georgia,  NSI Enterprises , Inc., ZEP Manufacturing  Company,  and NSI Services,
L.P. (collectively, referred to as the "Affiliates"); and

     WHEREAS, each Affiliate has assumed the obligation, with respect to certain
eligible employees employed by such Affiliate,  to provide benefits under one or
more of the Plans; and

     WHEREAS,  each of the Affiliates now desires to adopt and become a party to
the Trust upon the terms set forth herein; and

     WHEREAS,  the Corporation desires to amend the Trust in certain respects to
clarify  each  Affiliate's  financial  obligation  to  provide  benefits  to the
Affiliate's eligible employees under any Plan adopted by such Affiliate;

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

                                       1.

     The  Corporation  authorizes  each of the  Affiliates to adopt and become a
party to the Trust in accordance with the terms and provisions thereof.



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Exhibit 10(iii)A(13)(b)


                                       2.

     Effective as of August 31, 1996,  each of the Affiliates  hereby adopts and
becomes  a party to the  Trust  and  agrees  to be bound  by all the  terms  and
provisions thereof.

                                       3.

     Section 4.1 of the Trust is hereby  amended by deleting the first  sentence
thereof in its entirety and substituting the following:

          "Immediately  upon the occurrence of a Change in Control,  the Company
     and  each  Affiliate  shall   contribute   sufficient  cash  or  marketable
     securities to their  respective  Benefit Accounts in an amount equal to the
     difference  between the assets  transferred  to this Trust  pursuant to the
     Transfer  and the amount  necessary to pay all  benefits  payable  (whether
     payable  currently or on a deferred basis) under all  Transferred  Plans as
     the  Trustee,  in  its  discretion,   determines;  provided,  however,  any
     Affiliate  shall be required to make  contributions  hereunder  only to the
     extent of such Affiliate's obligation under each Plan it has adopted."

                                       4.

     Section 4.2 of the Trust is hereby  amended by adding  "and any  Affiliate"
after "Company" wherever it appears therein.

                                       5.

     Section  4.3 of the Trust is hereby  amended  by adding "or  Affiliate,  as
applicable"  after  "Company"  wherever  it  appears  therein  and by adding the
following to the end of the section:

     "In the event that any Affiliate fails to transfer funds following  written
     demand as  provided  herein,  the  Company  shall  assume  the  Affiliate's
     obligation to transfer such funds."

                                       6.

     Section 9.4 of the Trust is hereby  amended by adding the  following to the
end of the section:

     "To the extent any Affiliate has failed to transfer  funds  required  under
     Section  4.3,  the  Trustee  may join such  Affiliate  in any legal  action
     against the Company to compel payment."

                                       7.


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                                                         Exhibit 10(iii)A(13)(b)



     This Agreement shall be effective as of August 31, 1996. Except as provided
herein,  the  remaining  provisions  of the Trust shall remain in full force and
effect.

     IN WITNESS  WHEREOF,  the parties  hereto have executed this  Amendment and
Adoption Agreement as of the day and year first written above.

ATTEST:                                     NATIONAL SERVICE INDUSTRIES, INC.

____________________________                By: _______________________________

ATTEST:                                     NORTH BROS., INC.

____________________________                By: _______________________________

ATTEST:                                     NATIONAL SERVICE INDUSTRIES, INC. OF
                                                     GEORGIA

____________________________                By: _______________________________

ATTEST:                                     NSI ENTERPRISES, INC.

____________________________                By: _______________________________

ATTEST:                                     ZEP MANUFACTURING COMPANY

____________________________                By: _______________________________

ATTEST:                                     NSI SERVICES, L.P.

____________________________                By: _______________________________


ATTEST:                                     WACHOVIA BANK AND TRUST COMPANY,
                                                     AS TRUSTEE

____________________________                By: _______________________________