<ARTICLE> 5 <LEGEND> THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE UNAUDITED CONSOLIDATED FINANCIAL STATEMENTS OF COSTILLA ENERGY, INC. FOR THE QUARTER ENDED SEPTEMBER 30, 1999 AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH 10-Q. </LEGEND> <MULTIPLIER> 1,000 <PERIOD-TYPE> 9-MOS <FISCAL-YEAR-END> DEC-31-1999 <PERIOD-START> JAN-01-1999 <PERIOD-END> SEP-30-1999 <CASH> 3,894 <SECURITIES> 0 <RECEIVABLES> 10,546 <ALLOWANCES> 842 <INVENTORY> 0 <CURRENT-ASSETS> 14,211 <PP&E> 179,633 <DEPRECIATION> 90,680 <TOTAL-ASSETS> 123,461 <CURRENT-LIABILITIES> 52,887 <BONDS> 181,608 <PREFERRED-MANDATORY> 0 <PREFERRED> 5 <COMMON> 1,410 <OTHER-SE> (123,094) <TOTAL-LIABILITY-AND-EQUITY> 123,461 <SALES> 10,977 <TOTAL-REVENUES> 11,136 <CGS> 3,601 <TOTAL-COSTS> 4,074 <OTHER-EXPENSES> 8,938 <LOSS-PROVISION> 0 <INTEREST-EXPENSE> 4,061 <INCOME-PRETAX> (5,937) <INCOME-TAX> 0 <INCOME-CONTINUING> (5,937) <DISCONTINUED> 0 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> (5,937) <EPS-BASIC> (.42) <EPS-DILUTED> (.42)