The authors developed a therapeutic regimen in which 33 patients aged I I to 61 years (mean 2 SE, 35.9 t 2.3 years) with acute myeloid leukemia (AML) were given intensive induction chemotherapy with Adriamycin (doxorubicin) (ADM), vincristine (VCR) and cytosine arabinoside (ARA-C). Twenty-nine of these patients (88%) attained a complete remission (CR) after I, 2, or 3 courses, and were then subjected to an early consolidation course of chemotherapy, identical to that for induction. After consolidation, all patients in CR received a long-term continuous maintenance therapy in which 6-mercaptopurine (6-MP) and methotrexate (MTX) were alternated, associated with periodic reinforcements with daunorubicin (DNR) and VCR. Twenty-five of the 29 patients who achieved a CR were splenectomized soon after the consolidation course. Histologic sections of the spleens, liver biopsy specimens, and lymph nodes, stained routinely and with the naphtol AS-D chloroacetate esterase (NCA) method, showed mature granulocytes and a few NCA positive mononuclear cells, but no proved leukemic infiltrates. For the 25 splenectomized patients, the probability of remaining in CR at 36 and 54 months was 75% and 66%, respectively; the probability of survival at 36 and 54 months was 85% and 75%, respectivelj. Age older than 40 years and evidence of extramedullary involvement a t presentation appeared to carry a bad prognosis for diseasefree survival.