Eight patients, 5 with acute non lymphoid leukemia and 3 with lymphoid leukemia, were treated at relapse after bone marrow transplantation (BMT; 4 autologous BMT and 4 allogeneic BMT). Of these, 2 relapsed within 3 months after BMT (2 allogeneic BMT) and 6 (2 allogeneic and 4 autologous BMT) after more than 9 months after BMT. The 2 patients relapsing early showed no response to treatment and died. Five out of 6 patients relapsing late achieved complete remission (4 of them with intensive chemotherapy). Four patients are currently alive. Aggressive combination chemotherapy can produce long-term survival in selected patients relapsed after BMT.