Twenty children with acute leukemia between 3 and 19 years of age underwent allogeneic bone marrow transplantation from HLA-matched sibling donors after conditioning with total-body irradiation (1,200 cGy in six fractions of 200 cGy twice daily for 3 days) and high dose cytosine arabinoside (3 g/m2 given every 12 hours for 12 doses). Three patients died with acute toxicity. Six patients developed grade II acute graft versus host disease. With a median follow-up of 68 months (range 26–96 months), thirteen children (65%) are alive and in remission with Karnofsky scores of 90–100%. A patient with AML in resistant relapse went into remission but relapsed and died 5 months post-transplantation. Three other patients relapsed, 8, 12, and 16 months post BMT. Our results suggest that this conditioning regimen is associated with high but manageable acute toxicity and may be highly effective in controlling leukemia resistant to conventional chemotherapy. © 1995 Wiley-Liss, Inc.