A 68-year-old male had end-stage renal disease secondary to hypertension. He was placed on chronic dialytic therapy and was given recombinant human erythropoietin (epoetin) for renal anemia. One month later, rapidly progressing anemia was noted. The anemia was unresponsive to maximal doses of epoetin and the patient soon became transfusion-dependent. Erythroid hypoplasia was demonstrated by bone marrow biopsy. A detailed search for the cause of the erythroblastopenia revealed nothing. A diagnosis of acquired pure red cell aplasia was made. The use of immunosuppressive agents improved the patient's symptoms and laboratory data. Antibodies for erythropoietin (EPO) were negative after the treatment. It is suggested that patients with EPO-resistant anemia with no obvious etiology should be examined for underlying hematologic disorders.