Fourteen consecutive patients with chronic myelogenous leukemia (CML) blast crisis were treated with a more dose-intensive regimen of daunorubicin (70 mg/m2 per day on days 1-3) and cytosine arabinoside (200 mg/m2 per day as continuous infusion on days 1-9) than usually used in de novo acute myelogenous leukemia. The median age of the patients was 50 years (27-78 years). Eleven of 13 evaluable patients were aplastic at day 14 after a single course of therapy (11/13, 85%). Over-all response rate (complete + partial response) was 9/13 (69%). Restoration to chronic phase was achieved in 7/13 patients (54%) lasting a median of 78 days (49-235 days). However, four of these seven patients proceeded to bone marrow transplant (BMT) and so the true remission duration for this therapy cannot be determined. Treatment-related mortality was 4/14 (29%). Presently, four of nine patients evaluable are surviving post-induction, three S/P allogeneic BMT (0.6, 3.8, 5 years) and one patient S/P autologous BMT (3.3 years post-induction). These results of an intensive induction regimen achieving marrow aplasia in all except one patient to date warrants further study as the first step possibly towards BMT after CML blast crisis.