The objective of this study was to compare allogeneic bone marrow transplantation (BMT) with high-dose cytarabine containing chemotherapy in children with acute myeloid leukemia (AML) in first complete remission (CR). One hundred and seventy-one children were enrolled on the LAME89/91 protocol. Induction chemotherapy was a combination of cytarabine and mitoxantrone. After achieving CR, patients who had an HLA-identical sibling donor underwent allogeneic BMT. Children not eligible for BMT received post remission chemotherapy which included two consolidation courses, the second consolidation consisting of high-dose cytarabine with amsacrine and asparaginase. CR was achieved in 149 children (87%). Thirty-two had an HLA-identical sibling donor and were eligible for BMT. These 32 patients, as well as an additional child who had a one antigen HLA-mismatched father, received BMT during first CR. Consequently, 33 patients were analyzed in the BMT group and 116 in the chemotherapy group. The 4-year probability of relapse was 26 +/- 15% in the BMT group and 47 +/- 10% in the chemotherapy group (P = 0.04). The risk of therapy-related death was 3% for BMT and 7.7% for chemotherapy. Disease-free survival (DFS) was 72 +/- 15% in the BMT group and 48 +/- 10% in the chemotherapy group (p = 0.02). We conclude that allogeneic BMT from a matched sibling donor is the treatment of choice for reducing the relapse risk and for increasing DFS in children with AML in first CR.