<PAGE>   1
                                                                Exhibit 12
                 THE COLUMBIA GAS SYSTEM, INC. AND SUBSIDIARIES

                Statements of Ratio of Earnings to Fixed Charges
                                ($ in millions)


<TABLE>
<CAPTION>
                                                            TWELVE MONTHS                           TWELVE MONTHS
                                                          ENDED SEPTEMBER 30,                     ENDED DECEMBER 31,
                                                          -------------------    -------------------------------------------------
                                                            1996        1995        1995      1994      1993      1992      1991
                                                            ----        ----        ----      ----      ----      ----      ----
<S>                                                         <C>         <C>         <C>       <C>       <C>       <C>       <C>
Consolidated Income (Loss) from Continuing Operations
 before Income Taxes, Extraordinary Item and Cumulative
 Effect of Accounting Change  . . . . . . . . . . . . .   (692.3)      400.5      (643.0)    392.2     288.1     161.4  (1,205.8)

Adjustments:
  Interest during construction  . . . . . . . . . . . .    (21.2)          -       (20.2)        -         -         -      (3.4)
  Distributed (Undistributed) equity income . . . . . .      3.6        (9.4)       (7.9)     (0.9)     (0.1)     (0.1)     (2.4)
  Fixed charges   . . . . . . . . . . . . . . . . . . .  1,160.8        22.5     1,040.8      14.8     101.5      13.7     139.9
                                                         -------     -------     -------   -------   -------   -------   -------
    Earnings Available  . . . . . . . . . . . . . . . .    450.9       413.6       369.7     406.1     389.5     175.0  (1,071.7)
                                                         -------     -------     -------   -------   -------   -------   -------
Fixed Charges:
  Interest on long-term and short-term debt              1,100.1         0.4       987.2       0.7       3.1       4.9     112.4
  Other interest  . . . . . . . . . . . . . . . . . . .     60.7        22.1        53.6      14.1      98.4       8.8      27.6
                                                         -------     -------     -------   -------   -------   -------   -------
    Total Fixed Charges before Adjustments*,**. . . . .  1,160.8        22.5     1,040.8      14.8     101.5      13.7     140.0
                                                         -------     -------     -------   -------   -------   -------   -------
Adjustments:                                                                                                       

  Gain/(Loss) on reacquired debt  . . . . . . . . . . .       -           -            -         -         -         -      (0.1)
                                                         -------     -------     -------   -------   -------   -------   -------
    Total Fixed Charges   . . . . . . . . . . . . . . .  1,160.8        22.5     1,040.8      14.8     101.5      13.7     139.9
                                                         -------     -------     -------   -------   -------   -------   -------
Ratio of Earnings Before Taxes to Fixed Charges            N/A(a)      18.38       N/A(a)    27.44      3.84     12.77     N/A(a)
</TABLE>


(a)To achieve a one-to-one coverage, the Corporation would need an additional
$709.9, $671.1 and $1,211.6 million of earnings, for the twelve months ended
September 30, 1996, and the twelve months ended December 31, 1995 and 1991,
respectively.

 *       This amount excludes approximately $261 million interest expense not
         recorded in the twelve months ended September 30, 1995, $230 million,
         $210 million, $204 million and $86 million of interest expense not
         recorded for 1994, 1993, 1992 and 1991.  Includes interest expense of
         $982.9 million including write-off of unamortized discounts on
         debentures recorded in 1995. Reference is made to the Statements of
         Consolidated Income for the quarterly period ended September 30, 1996,
         as reported in Form 10-Q.


**       This amount excludes $8.6 million of interest expense not recorded
         with respect to the registrant's guarantee of LESOP Trust's debentures
         for the twelve months ended September 30, 1995.  Also excluded are $8.6
         million, $8.6 million, $8.6 million and $15.5 million of interest
         expense not recorded with respect to the registrant's guarantee of
         LESOP Trust's debentures for the twelve months ended December 31,
         1994, 1993, 1992 and 1991, respectively.