Eleven patients received allogeneic bone marrow from all HCA-identical sibling for the treatment of acute leukemia. The preparative regiment included high-dose cytosine arabinoside (Ara-C), 3 g/m2q 12 h for 12 doses, and 1000 rad single-fraction total body irradiation (5 patients) or 1200 rad fractionated total body irradiation (6 patients). The 5 patients receiving the 1000 rad single-fraction regimen were transplanted in relapse, while the 6 patients receiving the 1200 rad fractionated program were transplanted during remission. Both regimens were well-tolerated, but the single-dose radiation regimen was associated with more severe skin problems. Bone marrow engraftment was documented in 10 of 10 evaluable patients, occurring 2-3 weeks after marrow infusion. No recurrences have been observed during the brief follow-up time.