Page 61
                                                        Exhibit 10(iii) A(23)(b)


                                 AMENDMENT NO. 1
                                       TO
                        NATIONAL SERVICE INDUSTRIES, INC.
                       SUPPLEMENTAL DEFERRED SAVINGS PLAN



     THIS  AMENDMENT  made as of this 29th day of  December,  1997,  by NATIONAL
SERVICE INDUSTRIES, INC.
(the "Company");


                              W I T N E S S E T H:


     WHEREAS,   the  Company   previously   established  the  National   Service
Industries,   Inc.  Supplemental  Deferred  Savings  Plan  ("Plan"),   effective
September 18, 1996; and


     WHEREAS,  the  Company  now  desires  to  amend  the  Plan  in  the  manner
hereinafter provided;


     NOW,  THEREFORE,  for and in  consideration  of the  premises,  the Plan is
hereby amended as follows:


                                       1.


     Section  4.1(a) is hereby amended by adding the following to the end of the
present section:


                  "If permitted by the Company and in accordance with such rules
         as the Company may  establish,  a Participant  (other than an Executive
         Officer  of the  Company)  may  direct  that  all or a  portion  of the
         Deferral Subaccount shall be deemed to be invested in Shares."


                                       2.


     Section  4.1(b) is hereby  amended by deleting  the present  section in its
entirety and substituting the following in lieu thereof:


                  "(b)  Matching  Subaccount.  As of the end of each Plan  Year,
         unless the Board otherwise  determines,  there shall be credited to the
         Matching Subaccount of each Participant who is employed on the last day
         of  the  Plan  Year  an  amount  equal  to 25%  of  the  amount  of the
         Participant's  deferrals for such Plan Year,  provided that the maximum
         amount credited to a Participant's  Matching Subaccount for a Plan Year
         shall not exceed five  percent (5%) of the  Participant's  Compensation
         for such Plan  Year.  Unless the  Company  otherwise  determines  for a
         designated  Eligible  Executive (other than an Executive Officer of the
         Company),  an Eligible  Executive  who is covered by a defined  benefit
         supplemental executive retirement plan maintained by the Employer shall
         not be eligible to receive Employer matching contribution credits under
         the Plan.


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                                                        Exhibit 10(iii) A(23)(b)


                  Unless the Company otherwise  determines,  the amount credited
         to a Participant's  Matching  Subaccount shall be deemed to be invested
         in the form of cash,  Shares,  or a combination of cash and Shares,  as
         elected by the  Participant  on the  Election  Form.  The  Company  may
         provide the Participant with the right to change the deemed  investment
         election from time to time and to designate different deemed investment
         elections for amounts credited to the Matching  Subaccount in different
         Plan Years.  To the extent the amount is deemed to be credited in cash,
         the Matching  Subaccount  will be credited  with  interest at the Prime
         Rate on each Annual Valuation Date (and at such other dates, if any, as
         may be determined by the Plan  Administrator);  if Shares are deemed to
         be credited,  the Matching  Subaccount  will be adjusted on each Annual
         Valuation  Date (and at such other dates ,if any, as may be  determined
         by the Plan  Administrator) as if it were invested in Shares to reflect
         any dividends  (including  reinvestment  of such  dividends in Shares),
         distributions,  stock  dividends,  stock splits or similar actions with
         respect to the Shares since the  preceding  Annual  Valuation  Date (or
         such other date)."


                                       3.


     Section  4.1(c) is hereby  amended by adding the following at the beginning
of the last sentence of the first paragraph of the present section:

                  "Unless the Company otherwise determines for a designated
                   Eligible Executive,"


                                       4.


     Section  4.3(a)(iii)(B) is hereby amended by deleting the present provision
in its entirety and substituting the following in lieu thereof:


                  "(B) In the event a Participant  terminates after completing 5
         Years of Service and  attaining  age 55 (except for death and Total and
         Permanent  Disability  which are  covered  by (A)  above),  the  vested
         balance  credited  to a  Participant's  Deferral  Subaccount  shall  be
         distributed as follows:  (x) any Class Year  Subaccounts as to which he
         has properly elected under subsection (ii) above a delayed distribution
         and/or payment in installments  shall be distributed in accordance with
         such elections;  and (y) with respect to any Class Year  Subaccounts as
         to which  the  five-year  period  has not yet  passed  and  that  would
         otherwise  be  payable  more  than  one  (1)  year in the  future,  the
         Participant  may  elect  prior  to  termination  to make  the  deferral
         election  in (ii)  above.  Any Class Year  Subaccounts  as to which the
         5-year  period has not passed that are payable  within one (1) year and
         any Class Year  Subaccounts as to which the election in (y) is not made
         shall be payable as soon as practical after termination."

                                                                         Page 63
                                                        Exhibit 10(iii) A(23)(b)


                                       5.


     Section  4.3(b)(ii) is hereby amended by adding the following at the end of
the first paragraph of the present section:


                  "If the  Participant  does not elect to receive a distribution
         in  Shares,   or  if  Shares  cannot  otherwise  be  distributed,   the
         Participant's benefits shall be paid in cash."

                                       6.


     The within and  foregoing  amendments  to the Plan shall be effective as of
December 1, 1996. Except as hereby modified, the Plan shall remain in full force
and effect.


     IN WITNESS  WHEREOF,  the undersigned has executed this Amendment No. 1 the
day and year first above written.

                                               NATIONAL SERVICE INDUSTRIES, INC.

                                               By:  /s/ James S. Balloun
                                               ---------------------------------