<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE
FINANCIAL STATEMENTS OF ARONEX PHARMACEUTICALS, INC. SET FORTH IN THE COMPANY'S
FORM 10-Q FOR THE NINE MONTHS ENDED SEPTEMBER 30, 1999 AND IS QUALIFIED IN ITS
ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>

                             
<PERIOD-TYPE>                   9-MOS
<FISCAL-YEAR-END>                          DEC-31-1998
<PERIOD-END>                               SEP-30-1999
<CASH>                                      15,884,000
<SECURITIES>                                 8,442,000
<RECEIVABLES>                                  857,000
<ALLOWANCES>                                         0
<INVENTORY>                                          0
<CURRENT-ASSETS>                            24,823,000
<PP&E>                                       5,445,000
<DEPRECIATION>                               3,319,000
<TOTAL-ASSETS>                              27,876,000
<CURRENT-LIABILITIES>                        4,354,000
<BONDS>                                              0
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                        23,000
<OTHER-SE>                                  19,881,000
<TOTAL-LIABILITY-AND-EQUITY>                27,876,000
<SALES>                                              0
<TOTAL-REVENUES>                            11,757,000
<CGS>                                                0
<TOTAL-COSTS>                                        0
<OTHER-EXPENSES>                            18,805,000
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                             257,000
<INCOME-PRETAX>                            (7,305,000)
<INCOME-TAX>                                         0
<INCOME-CONTINUING>                        (7,305,000)
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                               (7,305,000)
<EPS-BASIC>                                     (0.34)
<EPS-DILUTED>                                   (0.34)