<PAGE>
                                                                      EXHIBIT 12


                            Atmos Energy Corporation
                    Computation of Earnings to Fixed Charges



<Table>
<Caption>
                                                        Year Ended September 30
                                          ----------------------------------------------------
                                            2002       2001       2000       1999       1998
                                          --------   --------   --------   --------   --------
<S>                                       <C>        <C>        <C>        <C>        <C>
Income from continuing operations
     before provision for income taxes
     per statement of income              $ 94,836   $ 89,458   $ 56,237   $ 27,299   $ 87,071
Add:
     Portion of rents representative of
       the interest factor                   3,614      2,917      3,007      3,520      3,050
     Interest on debt & amortization
       of debt expense                      59,174     47,011     43,823     37,063     35,579
                                          --------   --------   --------   --------   --------
        Income as adjusted                $157,624   $139,386   $103,067   $ 67,882   $125,700
                                          ========   ========   ========   ========   ========

Fixed charges:
     Interest on debt & amortization
       of debt expense (1)                $ 59,174   $ 47,011   $ 43,823   $ 37,063   $ 35,579
     Capitalized interest (2)                1,272      1,494         --      3,724      4,132
     Capitalized expenses related
       to indebtedness (3)                      --      4,718         --         --         --
     Rents                                  10,842      8,752      9,020     10,560      9,149
     Portion of rents representative of
       the interest factor (4)               3,614      2,917      3,007      3,520      3,050
                                          --------   --------   --------   --------   --------
        Fixed charges (1)+(2)+(3)+(4)     $ 64,060   $ 56,140   $ 46,830   $ 44,307   $ 42,761
                                          ========   ========   ========   ========   ========

Ratio of earnings to fixed charges            2.46       2.48       2.20       1.53       2.94
</Table>


