Background: Anemia in chronic renal failure plays an important role in increasing morbidity of dialysis patients. The causes of the anemia are multifactorial. With using of erythropoietin(EPO) most of uremia-induced anemia can be overcome. However, about 10% of renal failure patients shows EPO-resistant anemia. Hyporesponsiveness to EPO has been related to many factors: iron deficiency, aluminum intoxication, inflammations, malignancies and secondary hyperparathyroidism. So I evaluated the improvement of EPO responsiveness after correction of above several factors. Materials and Methods: Seventy-two patients on hemodialysis over 6 months were treated with intravenous ascorbic acid(IVAA, 300 mg t.i.w. for 12 weeks), After administration of IVAA for 12 weeks, patients were classified into several groups according to iron status, serum aluminum levels and i-PTH levels. Indivisualized treatments were performed: increased iron supplement for absolute iron deficiency, active vitamin D3 for secondary hyperparathyroidism and desferrioxamine(DFO, 5 mg/kg t.i.w.) for aluminum intoxication or hyperferritinemia. Results: 1) Result of IVAA therapy for 12 weeks on all patients(n=72). Hemoglobin levels at 2, 4, 6 week were significantly elevated compared to baseline, but those of hemoglobin at 8, 10, 12 week were not significantly different. 2) Result of IVAA therapy for 20 weeks on patients with 100 ${\mu}g/l$ ${\leq}$ ferritin < 500 ${\mu}g/l$ and transferrin saturation(Tsat) below 30%(n=30). After treatment of IV AA for 12 weeks, patients were evaluated the response of therapy according to iron status. Patients with 100 ${\mu}g/l$ ${\leq}$ ferritin < 500 ${\mu}g/l$ and Tsat below 30% showed the most effective response. These patients were treated further for 8 weeks. Hemoglobin levels at 2, 4 week were significantly increased compared to baseline with significantly reduced doses of EPO at 2, 4, 6, 10, 12, 16, 20 week. Concomitantly significantly improvement of Tsat at 2, 6, 16, 20 week compared to baseline were identified. 3) Result of IVAA therapy for 12 weeks followed by DFO therapy for 8 weeks on patients with serum aluminum above 4 ${\mu}g/l$(n=12) Hemoglobin levels were not significantly increased during IVAA therapy for 12 weeks but dosages of EPO were significantly decreased at 2, 4, 6, 8 week during DFO therapy compared to pre-treatment status. Conclusion: IVAA can be helpful for the treatment of the anemia caused by functional iron deficiency and can reduce the dosage of EPO for anemia correction. And administration of low dose DFO, in cases of increased serum aluminum level, can reduce the requirement of EPO.