During the 12-year period between 1971 and 1982 leukemia was diagnosed in 759 children in Hungary. Of these, 123 (16%) had acute myeloid or myelomonocytic leukemia. This corresponds to an annual incidence rate of 6.15 cases per 10(6) children. Analysis of the presentation symptoms at diagnosis showed a higher incidence of septic signs but otherwise no difference to those in acute lymphoid leukemia. Treatment schedules were intensified successively in stepwise fashion. Remission rates rose from 34% to 66%, and remission lengths also improved. Of the prognostic factors analyzed, initial WBC count in excess of 50 G/1 was found to confer bad prognosis, while the other factors had no significant effect on disease-free survival.