Five patients with myelofibrosis and three with chronic lymphocytic leukemia (CLL) who had erythroblastopenic anemia refractory to antineoplastic therapy were treated with oxymetholone, 1.6 to 2.4 mg/kg of body weight per day. Four of the five patients with myelofibrosis and all three with CLL had a decrease in transfusion requirements and a mean maximum increase in hemoglobin concentration of 105%. Platelet counts increased in four of eight cases, and leukocyte counts increased in three of four leukopenic patients. Discontinuation of oxymetholone therapy or a decrease in dose below 1.0 mg/kg/day nearly always resulted in a relapse of the anemia. Mild hepatotoxicity was observed in four, virilization in two, hyperuricemia in one, and edema in all patients. Oxymetholone is at least as effective as other anabolic steroids in erythroblastopenic myelofibrosis and CLL and may be the treatment of choice.