Three children with acute nonlymphocytic leukemia in first remission were given cyclophosphamide (60 mg/kg on each of 2 days), fractionated total-body irradiation (total 12 Gy, six fractions), and a marrow transplant from an HLA-identical, mixed lymphocyte culture-negative sibling. All three patients are alive in a leukemia-free state 12 to 25 mo after transplantation. There were very few complication, other than mild graft-versus-host disease that developed in two patients. No interstitial pneumonitis and no serious infections have occurred. Long-term disease-free survival is expected in these patients.