Anthracycline and cytosine arabinoside are used in combination as the standard therapy for remission induction of acute nonlymphoblastic leukemia. Idarubicin, a synthetic daunorubicin analogue, shows an improved spectrum activity and diminishes acute or chronic toxicity when compared with the other anthracyclines. This study has been carried out in our clinic in order to evaluate the efficiency of the acute nonlymphoblastic leukemia protocol which includes idarubicin. Thirty-eight patients admitted to our Department between 1992-1999 and diagnosed as acute nonlymphoblastic leukemia (ANLL) were included in the study. Their median age was 7 years 6 months (range, 8 months to 14 years). Induction therapy consisted of idarubicin plus cytosine arabinoside and etoposide. Consolidation therapy consisted of two courses, followed by maintenance therapy with thioguanine, cytosine arabinoside, vincristine and cyclophoshamide. The complete remission rate was found to be 71%. The overall survival estimate was found to be 40% for one year and 23% for three years. We established that the protocol with idarubicin reached a higher remission ratio when compared with the other protocols with anthracycline. However, the degree of the hematologic toxicity ratios related to the therapy increased the complication ratios, which affected the long-term life analyses directly. Therefore this protocol may be revised according to socioeconomical conditions, especially in the developing countries.