Over a 10-year period 120 patients (58 women, 62 men; median age 33 [14-53] years) with acute myeloid leukaemia were treated by allogenic (n = 90) or autologous bone marrow transplantation to maintain remission. After a median observation time of 41 (11-126) months 64 patients (53%) remain alive without recurrence of leukaemia. Ten years after allogenic transplantation performed during the first complete remission the probability of disease-free survival is 50 +/- 8%, as compared with 50 +/- 9% at 4.5 years after autologous transplantation. Significant factors influencing disease-free survival after allogenic transplantation during the first complete remission were the time interval up to the onset of remission and the length of the remission before transplantation. The chance of disease-free survival after allogenic transplantation in the second complete remission does not so far differ from the results achieved by transplantation in the first complete remission. The risk of recurrence after autologous transplantation in the first complete remission (47 +/- 10%) is significantly higher than that following allogenic transplantation (18 +/- 10%, P less than 0.0001). Acute graft versus host reactions occurred in 16% and chronic reactions in 36% of patients after allogenic transplantation. The mortality was 38% after allogenic transplantation and 7% after autologous transplantation.