Current observation was obtained for adults treated on a protocol for acute lymphoblastic leukemia, which was open from 1972 to 1978, in order to determine the long-term outcome and to evaluate potential prognostic factors. Long-term survival (five + years) was seen in 32% (25/79) of patients who achieved complete remission; 16/79 remain in first remission and 2/79 are currently in second remission. Young age (less than 40) and female sex were significant prognostic factors for long-term survival, but the basis for this advantage is unclear. Further improvements in chemotherapy are needed.