From December, 1985 to October, 1987, 16 patients aged from 14 to 62 (median 34) with acute leukemia in relapse (10 affected by ANLL and 6 by ALL) were treated with the following regimen: Idarubicin 12 mg/m2/day on days 1-2-3, Ara-C 600 mg/m2 twice a day from day 1 to 6. Twelve patients (75%) achieved complete remission (C.R.). Two (12%) died during the induction phase from alveolar pneumonitis. One patient was resistant. The median duration of C.R. and survival was respectively 12 (range 6 to 100 +) and 23 weeks (4 to 108 +). The median duration of granulocytopenia was 16 days (range 10 to 24 days). The most frequent non-hematological complications consisted of nausea, vomiting, diarrhea and mucositis. Four patients had hepatic and splenic microabscesses of suspected mycotic etiology, and one showed a transient cardiac arrhythmia. The C.R. rate obtained in this series may be considered satisfaying since all but 3 patients were on treatment at the time of relapse. Yet the short duration of C.R. suggests the opportunity of performing consolidation cycles or suprelethal therapy followed by bone marrow transplantation.