Since January 1988, 91 children with ANLL have been treated with a polychemotherapy regimen containing Mitoxantrone (MTZ), excluding other anthracyclines. Induction consisted of Ara-C, MTZ, and VP 16. Consolidation lasted 6 weeks with Vincristine, MTZ, Ara-C and 6-thioguanine (6TG), and was followed by 2 intensification courses combining High-dose Ara-C with respectively MTZ or VP 16. Maintenance therapy associated 6TG, Ara-C and MTZ up to a cumulative dose of 150 mg/m2. 91 patients are evaluable: 70 (76.9%) achieved complete remission, 59 (64.8%) after induction alone. There were 7 early deaths, 5 deaths in complete remission, and 17 relapses. Major toxic side effects were observed during the consolidation phase, mainly infectious complications, and the median duration of neutropenia was 82 days in this phase, leading to decrease the MTZ dose from 10 to 8 mg/m2. The event-free survival at three years is 38%. Cardiac toxicity is presently absent in children without previous cardiopathy.