Twenty-eight adult patients with primary refractory or relapsed acute leukemia were treated. The regimens consisted of mitoxantrone plus cytosine arabinoside for 17 patients with acute non-lymphocytic leukemia (ANLL) and mitoxantrone accompanied with vincristine and prednisolone for 11 patients with acute lymphoblastic leukemia (ALL). In primary refractory patients, 1 of the 4 (25%) ANLL and 1 of the 3 (33%) ALL attained complete remission (CR). Excluding 2 patients who underwent bone marrow transplantation, 8 of the 13 (62%) relapsed ANLL and 4 of the 8 (50%) relapsed ALL achieved CR with a median duration of remission of 6.2 months and 3.8 months, respectively. Myelosuppression occurred in all treatment courses and was associated with pyrexia due to infections in 84% of the cases. Nausea, vomiting and stomatitis were mild. Abnormal liver function tests were observed in 8 (28%) patients. One patient, pretreated with 550 mg/m2 of doxorubicin, developed congestive heart failure. The results suggest that mitoxantrone is of value in the treatment of Chinese patients with refractory or relapsed acute leukemia.