A total of 40 evaluable patients were treated for blastic crisis of chronic myelogenous leukemia with mitoxantrone, 12 mg/m2 per day for three days and 5-azacytidine 150 mg/m2 per day for 5 days. Toxicity was primarily hematologic and was manageable. The overall response rate was 23%, including five complete responders, two partial responders, and two with hematologic improvement. Cytogenetic and immunophenotypic characterization of the leukemia was performed on all patients with aspirable bone marrow, and these results were correlated with response and survival, but did not have predictive value once the patient was in blastic crisis. Only initial platelet count (p = 0.02), hemoglobin (p = 0.03), and lower white blood cell count (p = 0.09) were somewhat predictive of response. Lack of hepatic involvement (p = 0.05), lower white blood cell count (0.05), and higher platelet count (p = 0.02) were predictive of prolonged survival. Although response did not strongly correlate with survival, one third of responders were alive at one year. This regimen produces results similar to those of other recently published regimens in this disease. Earlier intervention and more effective therapy is necessary in these patients.