The value of maintenance therapy after the achievement of complete remission in adult acute nonlymphocytic leukemia (ANLL) has never been clearly established. A randomized Eastern Cooperative Oncology Group (ECOG) study of postremission therapy compared outcomes in patients who received no further therapy to those administered long-term maintenance chemotherapy. Adverse results in the group administered no further therapy led to early termination of this trial after only 51 patients were randomized. Patients receiving no postremission therapy experienced significantly inferior remission durations (P = .002) compared with patients receiving maintenance therapy. All 26 patients in the group administered no postremission therapy have relapsed, with a median duration of remission of 4.1 months. In contrast, four of 25 patients (16%) who received maintenance therapy remain disease free, with a median duration of remission of 8.1 months.