Thirty children aged 1-15 years with acute lymphoblastic leukemia and acute nonlymphoblastic leukemia were transplanted from HLA-matched donors using two different preparative regimens: 18 patients were prepared with cyclophosphamide and total body irradiation (TBI) while 12 patients received busulphan and cyclophosphamide. Fifteen patients survived 7 to 74 months after transplant. The association of busulphan and cyclophosphamide is a well-tolerated preparation for bone marrow transplant in children with eradicating and immunosuppressive efficacy comparable to that of the well-experienced TBI-cyclophosphamide association.