<ARTICLE> 5 <CIK> 0000861838 <NAME> HYBRIDON INC <PERIOD-TYPE> 12-MOS <FISCAL-YEAR-END> DEC-31-1999 <PERIOD-START> JAN-01-1999 <PERIOD-END> DEC-31-1999 <CASH> 2,551,671 <SECURITIES> 0 <RECEIVABLES> 1,218,142 <ALLOWANCES> 0 <INVENTORY> 0 <CURRENT-ASSETS> 3,871,727 <PP&E> 21,070,205 <DEPRECIATION> 14,691,883 <TOTAL-ASSETS> 11,935,248 <CURRENT-LIABILITIES> 10,209,428 <BONDS> 7,798,123 <PREFERRED-MANDATORY> 0 <PREFERRED> 6,618 <COMMON> 0 <OTHER-SE> (6,095,182) <TOTAL-LIABILITY-AND-EQUITY> 11,935,248 <SALES> 6,186,136 <TOTAL-REVENUES> 7,000,881 <CGS> 0 <TOTAL-COSTS> 16,754,192 <OTHER-EXPENSES> 0 <LOSS-PROVISION> 0 <INTEREST-EXPENSE> 749,731 <INCOME-PRETAX> (10,503,042) <INCOME-TAX> 0 <INCOME-CONTINUING> (10,503,042) <DISCONTINUED> 0 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> (10,503,042) <EPS-BASIC> (0.93) <EPS-DILUTED> (0.93)