EXHIBIT 12

                                                                  "REVISED"
                                                    ULTRAMAR DIAMOND SHAMROCK CORPORATION
                                              COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGE
                                                        AND PREFERRED STOCK DIVIDENDS
                                                    (dollars in millions, except ratios)

                                                                  Year Ended December 31,
                                                                  ----------------------- 
                                                                                       
                                                   1997      1996          1995      1994      1993      1992
                                                   ----      ----          ----      ----      ----      ----
Earnings:
 Income before taxes                               275.2      37.2 (1)     141.1     220.7     197.3     133.4

Add: Fixed Charges                                 162.3     157.1         158.74    115.3     125.1     124.3
 Amortization of interest previously capitalized               0.3           0.2
 Losses of investees                                                         0.5                           1.1
Less: Capitalized interest                          (2.8)    (10.6)        (16.4)     (7.8)     (6.1)     (6.1)
 Undistributed earnings of investees                                                            (0.2)
Earnings as adjusted                               434.7     184.0         284.1     328.2     316.1     252.7
Computation of Fixed Charges:
 Interest expense                                  120.2     110.1         113.9      87.1      93.1      93.5
 Capitalized interest                                2.8      10.6          16.4       7.8       6.1       6.1
 Dividend requirement on preferred stock (2)         7.1       7.1           7.1       6.7       7.1       4.2
 Interest portion of lease commitments              32.2      29.3          21.3      13.7      18.8      20.5
Total Fixed Charges                                162.3     157.1         158.7     115.3     125.1     124.3
Ratio of Earnings to Fixed Charges (3)               2.7       1.2           1.8       2.8       2.5       2.0


(1)  Excludes merger and integration costs of $77.4 million.

(2)  The preferred  stock dividend  requirement  has been increased to an amount
     representing  the  pre-tax  earnings  which would be required to cover such
     dividend requirements.

(3)  For the purpose of  calculating  the ratio of  earnings  to fixed  charges,
     "earnings as adjusted"  consist of income  before income taxes after adding
     certain fixed charges as noted above.  "Fixed charges"  consist of interest
     expense,  amortization  of debt  discount  and a  portion  of rent  expense
     representative of the interest factor.