<PAGE>
                                                            Exhibit 10(iii)A(43)


                           NATIONAL SERVICE INDUSTRIES

                                    AMENDMENT
                                       TO
                             STOCK OPTION AGREEMENTS


      THIS AMENDMENT made and entered into as of the 24th day of July,
2001, by and between National Service Industries, Inc., a Delaware corporation
(the "Company") and Brock A. Hattox ("Optionee").

      WHEREAS, the Company has previously adopted the National Service
Industries, Inc. Long-Term Incentive Program ("LTIP") and the National Service
Industries, Inc. Long-Term Achievement Incentive Plan ("LTAIP") to provide
additional incentives to certain officers and key employees of the Company and
its Subsidiaries; and

      WHEREAS, the Optionee has been granted the Incentive Stock Options (ISOs)
and Nonqualified Stock Options (NQSOs) listed on Exhibits A, B, and C attached
hereto (collectively the "Options") under the LTIP and the LTAIP; and

      WHEREAS, the terms and conditions of the grants of the Options are
reflected in Stock Option Agreements (the "Stock Option Agreements") between the
Company and Optionee; and

      WHEREAS, the Company and the Optionee desire to amend the Stock Option
Agreements for the Options in the manner hereinafter provided;

      NOW, THEREFORE, the parties agree as follows:

                                       1.

      Each of the Stock Option Agreements for the Options listed on Exhibit A
attached hereto is hereby amended to renumber the existing Section 6.1 as
Section 6.1(a) and to insert the following as a new subsection 6.1(b):

            "(b) Termination After Attaining Age 55. If the Optionee terminates
      employment (other than as a result of death or Disability) after attaining
      age 55 but prior to age 65, unless the Committee determines otherwise at
      the time of such termination, the Option shall continue to vest in
      accordance with the original schedule (just as if the Optionee had
      remained employed) and shall remain exercisable until five (5) years after
      the date of termination (but not beyond the Exercise Term). In the event
      of the Optionee's death after such termination, the Option shall continue
      to be exercisable in accordance with this subsection (b) as if the
      Optionee had lived and the Option shall be exercisable by the persons
      described in (a) above."
<PAGE>
                                       2.

      The Stock Option Agreement for the Option listed on Exhibit B attached
hereto is hereby amended to insert the following as a new subsection 6.2(d):

            "(d) Termination After Attaining Age 55. If the Optionee terminates
      employment (other than as a result of death or Disability) after attaining
      age 55 but prior to age 65, unless the Committee determines otherwise at
      the time of such termination, the Option shall continue to vest in
      accordance with the original schedule (just as if the Optionee had
      remained employed) and shall remain exercisable until five (5) years after
      the date of termination (but not beyond the Exercise Term). In the event
      of the Optionee's death after such termination, the Option shall continue
      to be exercisable in accordance with this subsection (d) as if the
      Optionee had lived and the Option shall be exercisable by the persons
      described in (a) above."

                                       3.

      Each of the Stock Option Agreements for the Options listed on Exhibit C
attached hereto is hereby amended to delete the existing Section 6.2 in its
entirety and to substitute the following in lieu thereof:

            "6.2  Termination of Employment Due to Specified Reasons.

                  If the Optionee's termination of employment is due to death,
Disability, Retirement (termination on or after age 65), termination by the
Company other than for cause, termination after attaining age 55, or voluntary
termination, the following shall apply:

            (a)   Termination Due To Death. In the event the Optionee dies while
                  actively employed, the Option shall remain exercisable until
                  seven (7) years after the date of grant or five (5) years
                  after the date of termination, whichever is later (but in any
                  event not beyond the Exercise Term), by (A) a Permitted
                  Transferee (as defined in Section 8 below), if any, or such
                  person(s) that have acquired the Optionee's rights under such
                  Option by will or by the laws of descent and distribution, or
                  (B) if no such person described in (A) exists, the Optionee's
                  estate or representative of the Optionee's estate.

            (b)   Termination by Disability. In the event the employment of the
                  Optionee is terminated by reason of Disability, the Option
                  shall remain exercisable until seven (7) years after the date
                  of grant or five (5) years after the date the Committee
                  determines the Optionee terminated for Disability, whichever
                  is later (but in any event not beyond the Exercise Term). In
                  the event of the Optionee's death after such termination, the
                  Option shall continue to be exercisable in accordance with
                  this subsection (b) as if the


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                  Optionee had lived and the Options shall be exercisable by the
                  persons described in (a) above.

            (c)   Termination by Retirement or by the Company Without Cause. In
                  the event the employment of the Optionee is terminated by
                  reason of Retirement (at or after age 65) or by the Company
                  for any reason other than for cause, the Option shall remain
                  exercisable until seven (7) years after the date of grant or
                  five (5) years after the date of termination, whichever is
                  later (but in any event not beyond the Exercise Term). In the
                  event of the Optionee's death after such Retirement or
                  termination, the Option shall continue to be exercisable in
                  accordance with this subsection (c) as if the Optionee had
                  lived and the Options shall be exercisable by the persons
                  described in (a) above.

            (d)   Termination After Attaining Age 55. In the event the Optionee
                  terminates employment (other than as a result of death or
                  Disability) after attaining age 55 but prior to age 65, unless
                  the Committee determines otherwise at the time of such
                  termination, the Option shall continue to vest in accordance
                  with the original schedule (just as if the Optionee had
                  remained employed) and shall remain exercisable until five (5)
                  years after the date of termination (but in any event not
                  beyond the Exercise Term). In the event of the Optionee's
                  death after such termination, the Option shall continue to be
                  exercisable in accordance with this subsection (d) as if the
                  Optionee had lived and the Options shall be exercisable by the
                  persons described in (a) above.

            (e)   Voluntary Termination. In the event Optionee voluntarily
                  terminates employment, the Options shall remain exercisable
                  until ninety (90) days after the date of termination (but not
                  beyond the Exercise Term)."

                                       4.

      This Amendment shall be effective as of July 24, 2001. Except as hereby
modified, the Stock Option Agreements shall remain in full force and effect.


      IN WITNESS WHEREOF, the undersigned have executed this Amendment as of the
day and year first written above.

                                            NATIONAL SERVICE INDUSTRIES, INC.

                                            By:_________________________________


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<PAGE>
                                            ____________________________________
                                            BROCK A. HATTOX


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<PAGE>
                                    Exhibit A

<TABLE>
<CAPTION>
               Expiration
Grant Date     Date         Plan ID      Grant Type    # Options    Option Price
--------------------------------------------------------------------------------
<S>            <C>          <C>          <C>           <C>          <C>
9/9/1996       9/9/2006     LTIP         ISO           10,524       $38.00
9/9/1996       9/9/2006     LTIP         NQSO          9,476        $38.00
</TABLE>


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<PAGE>
                                    Exhibit B

<TABLE>
<CAPTION>
               Expiration
Grant Date     Date         Plan ID      Grant Type    # Options    Option Price
--------------------------------------------------------------------------------
<S>            <C>          <C>          <C>           <C>          <C>
9/17/1996      9/17/2006    LTIP         NQSO          20,000       $38.00
</TABLE>


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<PAGE>
                                    Exhibit C

<TABLE>
<CAPTION>
               Expiration
Grant Date     Date         Plan ID      Grant Type    # Options    Option Price
--------------------------------------------------------------------------------
<S>            <C>          <C>          <C>           <C>          <C>
1/5/2000       1/5/2010     LTAIP        NQSO          65,001       $27.6875
10/4/2000      10/4/2010    LTAIP        NQSO          57,312       $19.4375
</TABLE>


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