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Exhibit 12
National Service Industries, Inc.
Ratio of Earnings to Fixed Charges
<TABLE>
<CAPTION>
Three Months Ended Nine Months Ended Year Ended
May 31 May 31 August 31
-------------------- -------------------- -----------
2000 1999 2000 1999 1999
-------------------- -------------------- -----------
Earnings:
<S> <C> <C> <C> <C> <C>
Income before taxes on income 33,950 48,635 106,932 128,992 198,322
Fixed charges 13,273 5,562 37,134 14,386 22,407
-------------------- --------------------- -----------
Total earnings 47,223 54,197 144,066 143,378 220,729
Fixed Charges:
Interest expense 11,723 4,184 32,474 10,252 16,895
Interest factor related to rentals 1,550 1,378 4,660 4,134 5,512
-------------------- --------------------- -----------
Total fixed charges 13,273 5,562 37,134 14,386 22,407
Ratio of Earnings to Fixed Charges 3.6 9.7 3.9 10.0 9.9
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</TABLE>