Chemotherapy of adults with acute nonlymphocytic leukemia has improved in recent years, yielding complete remissions in 65 per cent and cure in 10 to 15 per cent of all treated patients. Allogeneic bone marrow transplantation cures approximately one half of eligible young patients who gain an initial remission with chemotherapy. Autologous bone marrow transplantation may ultimately prove to be of value for the large numbers of patients who are over 40 years of age or who lack histocompatible siblings. Current investigative approaches in all these areas, based on insights into the pathophysiology of disease discussed in this article, should enhance the outcome for affected patients in the next decade.