A combination therapy with 5 aza-cytidine (5 AZA-C), vincristine (VCR), and prednisone (PRED) was given to 53 children with acute nonlymphocytic leukemia resistant to conventional therapy. Of these, eight children obtained a complete remission and seven a partial remission. Maintenance therapy was initiated in 12 children. The remission duration varied between 19 and 176 days (median 69 days). The main toxicity was vomiting and myelosuppression manifested as severe neutropenia and thrombocytopenia. It is concluded that VCR and PRED do not increase the response rate to that of 5 AZA-C as a single agent.