Fifteen bone marrow autotransplants (BMAT) in patients with acute myeloblastic leukemia (AML) were performed after the first remission. The mean age was 37 years (range 12 to 60 years). According to the morphological classification FAB, 8 patients had monocytic leukemia (M4, M5) and 7 myeloid leukemia (M1, M2, M3). The mean interval elapsed between the date of complete remission and the BMAT was 3.9 months (range 1 to 5-9 months). In 8 patients this interval was longer than 6 months and in 7 cases it was shorter than 6 months. After achievement of the complete remission all patients underwent certain cycles of intensification before the BMAT. Eight patients received only a cycle whereas 7 patients received more than one cycle (between 2 and 4). The conditioning protocol consisted of cyclophosphamide (CP) (60 mg/kg x 2) and total body radiotherapy (TBR) (10 Gy) in 9 patients; CP and busulfan in five; and CP, cytarabine at high doses and melphalan in one case. Marrow extraction was performed after completion of chemotherapy of intensification. In 5 cases the bone marrow was depleted of leukemic cells by previous in vitro treatment with ASTA-Z. There are at present 8 alive patients. The survival free of illness was 51.8%. Seven patients died: 3 cases because relapse of the leukemia, 3 due to attachment failure of the transplantation, and one patient suffered a viral myocarditis. The survival free of illness was significantly longer in those patients transplanted after 6 months of the complete remission.