Recombinant human erythropoietin is effective therapy for the anemia of chronic renal failure. Hypertension, seizures, dialysis access thromboses, and clotted dialyzers have been reported as problems associated with the use of this drug. To test the hypothesis that low-dose erythropoietin is effective and safe, we gave 37 chronic hemodialysis patients this compound (3,000 units, i.v.) three times each week for 3 months. Before and for 3 months during therapy, we measured hemoglobin, hematocrit, blood transfusions, blood pressure, access thromboses, seizures, and clotted dialyzers. After 2 months of treatment, mean hemoglobin concentration and mean hematocrit increased significantly. Five patients had no increase in either value. In 4 of these 5 nonresponders, blood loss accounted for treatment failure. Neither blood pressure nor the incidence of access thromboses, seizures, and clotted dialyzers changed during the 3 months of therapy. We conclude that recombinant human erythropoietin is effective as treatment for the anemia of chronic renal failure at much lower doses than have been reported previously. The low incidence of adverse events may be related to the low dose used.