We included HD patients with stable hematocrit (between 30~36%) under intravenous administration of CERA 100 μg once monthly for two months. Then they were shifted to receive CERA 50μg twice monthly for anther two months and finally they were shifted back to receive CERA 100 μg once monthly again for additional two months. Then we measured and compared the erythropoietic response (hematocrit, hemoglobin), profiles of iron status as well as nutritional status and inflammatory markers among the study subjects every two months for a total of 6 months. Those who had bleeding or received surgery or blood transfusion were excluded.