<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE
CONSOLIDATED FINANCIAL STATEMENTS OF ARONEX PHARMACEUTICALS, INC.  AND
SUBSIDIARIES SET FORTH IN THE COMPANY'S FORM 10-K FOR THE TWELVE MONTHS ENDED
DECEMBER 31, 1999 AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH
FINANCIAL STATEMENTS.
</LEGEND>
<MULTIPLIER> 1

                             
<PERIOD-TYPE>                   12-MOS
<FISCAL-YEAR-END>                          DEC-31-1999
<PERIOD-END>                               DEC-31-1999
<CASH>                                      11,528,000
<SECURITIES>                                 8,724,000
<RECEIVABLES>                                        0
<ALLOWANCES>                                         0
<INVENTORY>                                          0
<CURRENT-ASSETS>                            19,785,000
<PP&E>                                       5,479,000
<DEPRECIATION>                               3,450,000
<TOTAL-ASSETS>                              22,734,000
<CURRENT-LIABILITIES>                        4,486,000
<BONDS>                                              0
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                        23,000
<OTHER-SE>                                  14,708,000
<TOTAL-LIABILITY-AND-EQUITY>                22,734,000
<SALES>                                              0
<TOTAL-REVENUES>                            12,382,000
<CGS>                                                0
<TOTAL-COSTS>                                        0
<OTHER-EXPENSES>                                     0
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                             327,000
<INCOME-PRETAX>                           (14,094,000)
<INCOME-TAX>                                         0
<INCOME-CONTINUING>                       (14,094,000)
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                              (14,094,000)
<EPS-BASIC>                                     (0.65)
<EPS-DILUTED>                                   (0.65)