Extension of allogeneic transplants to older patients has been limited by a high risk of transplant-related death and graft-versus-host disease. To evaluate the feasibility in older patients, a retrospective analysis of the procedure was performed for first remission acute leukemia in 192 patients aged over 40 years and compared with a group of 1119 recipients aged from 16 to 40 years reported to the EBMT from 1986 to 1992. Patient-, disease-, and treatment-related variables were compared between the two age groups using the chi2 statistical method for categorical variables. Variables differing significantly or recognized as potential prognostic factors were included in a multivariate analysis. Leukemia-free survival and relapse were comparable among the age groups in the two types of leukemias. Incidence of graft-versus-host disease was higher in the older group of ALL patients. Older patients with AML in first remission had a higher treatment-related mortality incidence, with no influence on survival. A pair-matched analysis of AML patients did not show any statistical difference in the probability of LFS, RI, TRM, and survival for the two age cohorts of patients. These results suggest that BMT should be considered for patients over 40 years of age.