Infants with acute leukemia have a poor chance of being cured by conventional chemotherapy. We therefore treated cases of infant leukemia with high dose chemotherapy followed by bone marrow transplantation (BMT). Six suffered from acute leukemia and one from refractory anemia with excess of blasts (RAEB-t). The conditioning regimen consisted of busulfan (BU) and cyclophosphamide (CY), and was intensified by adding etoposide (VP) in four cases. At the time of BMT the children were 4, 5, 12, 13, 13, 14, and 20 months old. Three children were autografted, three received HLA-identical marrow from a sibling donor, and one child received matched unrelated donor marrow. All five children who were grafted in complete (CR) or partial remission (PR) are alive and well in CR 7, 13, 24, 37, and 46 months after allogeneic (two patients) or autologous (three patients) BMT, and 13, 17, 29, 42, and 53 months after initial diagnosis. The child with RAEB-t and the one transplanted in second chemotherapy-resistant relapse of acute non-lymphoblastic leukemia relapsed at 7 and 17 months respectively. The chemotherapy regimen was well tolerated. BU-CY-VP is a promising alternative treatment to regimens including total body irradiation for very young children suffering from acute leukemia.