By means of a national survey, records of 69 patients who underwent allogeneic bone marrow transplantation (BMT) from September 1975 through June 1983 were collected from 11 participating hospitals of the Total Body Irradiation (TBI) Subcommittee in Japan. The patients were divided into 34 with acute lymphocytic leukemia (ALL), and 35 with acute nonlymphocytic leukemia (ANLL). One-year survival rates were 47% and 25% in ALL and ANLL patients, respectively. Uninfected patients in remission at the time of BMT had significantly higher survival rates than the remaining patients. Significantly favorable prognostic factors were remission at the time of BMT, absence of infection at the time of BMT, younger age, preparation with low-dose-rate fractionated TBI and cyclophosphamide, and mild graft-versus-host disease (GVHD) for patients with acute leukemia treated with allogeneic BMT based on the external criterion variable of 180-day survival. By using Hayashi's quantification II, the ratios of correct discriminations for 180-day survival were calculated as 91% (31/34) and 86% (30/35) for ALL and ANLL, respectively.