In 204 adult patients with de novo acute myeloid leukemia (AML), we prospectively compared allogeneic bone marrow transplantation (alloBMT), autologous stem cell transplantation (ASCT) and chemotherapy (Chemo). 162 patients (79.4%) achieved a complete remission (CR). Of the 135 patients who were still in CR after consolidation, 96 patients were less than 46 years of age: 36 patients had an HLA-identical sibling donor and were allocated for alloBMT (group I); they were compared to the 60 other patients who did not have an HLA-identical sibling donor and were treated with either ASCT or chemotherapy (group II). The 3-year disease-free survival was higher for group I patients (66.5 +/- 16%) than for the 60 group II patients (42.4 +/- 13%) (P < 0.05). The actuarial risk of relapse at 3 years was significantly lower for group I patients (24 +/- 15%) than for the other 60 group II patients (56 +/- 13%; P < 0.009). By multivariate analysis, the disease-free survival and risk of relapse were influenced by the initial WBC count (P < 0.02 and P < 0.006), the number of chemotherapy courses for CR (P < 0.001 and P < 0.01) and the type of post-induction treatment (alloBMT vs no alloBMT; P < 0.1 and P < 0.02). The 99 patients who did not fulfill the inclusion criteria for alloBMT were given intensive chemotherapy including high-dose aracytine. When they were still in CR (n = 77), these patients were then randomized for either ASCT (n = 39) or Chemo (n = 38). We were unable to detect any statistical difference between ASCT and Chemo for either disease-free survival, risk of relapse or survival. These results indicate that alloBMT seems to produce results which are at least superior to those of other therapeutic modalities. The results of either ASCT or Chemo look similar.