Anemia is rapidly corrected by r-HuEPO in the majority of patients with end-stage renal disease provided that iron stores are carefully assessed. Serum ferritin, transferrin saturation and hypochromic red cells are parameters in evaluating the patients' iron status. Replenishment of diminished iron stores may be achieved using oral or intravenous iron. Vigorous iron substitution in r-HuEPO treated patients seems to be mandatory concerning public economy. The intravenous route is the way of choice in delivering sufficient iron supplementation not only in patients felt to be insensitive to standard r-HuEPO dose in therapy. The strategy for the most effective preservation of the iron storage pool and the optimal parameters for monitoring iron demand remains to be elucidated.