We have encountered five hemodialysis patients who had received enteral nutrition and recovered from erythropoietin- resistant anemia with neutropenia after the correction of copper deficiency. We reduced the required doses of recombinant human erythropoietin (rHuEPO) to maintain the target hematocrit levels and three patients were finally weaned from the rHuEPO therapy. Thus, copper deficiency is involved in erythropoietin-resistant anemia in hemodialysis patients.