Thirty-one unselected patients with untreated acute non lymphoblastic leukemia (ANLL) ranging in age from 15 to 76 years received two courses of a new high-dose induction regimen consisting of idarubicin, etoposide and cytarabine. Patients who entered complete remission (CR) were then allocated to post-remission intensification (PRI). Patients under 40 years of age with a HLA-compatible donor were given bone marrow transplantation (BMT); those without an HLA identical donor received either autologous BMT (ABMT) or no subsequent therapy. Twenty-five out of 31 patients (80.6%) achieved CR (93.3% in young and 68.7% in old patients) and 14 (56%) after the first cycle. Six patients (five out six greater than 40 years) died of cerebral hemorrhage and/or infection during the induction phase and four additional patients (three elderly) died on the PRI for the same cause without recurrent disease. Eleven out 25 patients are disease-free survivors 2-34 months (median 10 months) after achievement of CR. In conclusion, this intensive chemotherapy regimen is effective both in young and older patients but the post-remission intensification is too aggressive in elderly patients.