Sixteen patients with refractory acute non-lymphcytic leukemia (ANLL) were treated with 2 different therapeutic regimens including aclarubicin (ACR) and cytosine arabinoside (ara-C). ACR, 45mg/㎡, was administered daily by intravenous rapid infusion from, day 1 to 3 in Regimen 1, and the same dose of ACR, divided into 2 doses, was administered every 12 hours by intravenous infusion from day 1 to 3 in Regimen 2. Ara-C, 80mg/㎡, divided into 2 doses, was given every 12 hours by intravenous infusion from day 1 to 7 in Regimen 1 and 2. Seven of 10 patients, 70%, obtained a complete remission (CR) with Regimen 1, and 1 of 6 patients, 16.7%, with Regimen 2. The days required for CR ranged from 22 to 55 days (median: 40 days). The duration of CR ranged from 2 to 13 months (median: 9.3 months), and the survival from the initiation of therapy was from 9 to 41.3 months (median 19.6 months) in responders. Side effects on the digestive system such as nausea and vomiting were seen in 14 of 16 patients, 87.5%, but they were all controllable. The combination of ACR and ara-C, particularly Regimen 1, was also found to be more effective in the clinical management of refractory ANLL than a NCDVP (neocarzinostatin, area-C, daunorubicin, vincristine and prednisolone) regimen.