In patients with renal failure, severe anemia and associated fatigue, cognitive and sexual dysfunctions have a significant impact on the quality of life. Anemia also represents an important etiological factor in the development of left ventricular hypertrophy. An inadequate production of a glycoprotein hormone, erythropoietin (EPO), is the major cause of anemia in presence of a reduction in the glomerular filtration rate. EPO is the primary regulator of the growth and survival of the erythroid progenitor. The treatment of anemia in chronic renal failure has been revolutionized by the introduction of recombinant human EPO. The vast majority of patients responds very well to treatment, although 5-10% of patients shows some resistance to EPO, the most common cause of which is iron deficiency. Several studies have recently been started in order to investigate the effects of preventing renal anemia from ever developing in uremic patients. The hemoglobin concentration target in pre-dialysis and dialysis patients is the subject of continuous re-assessment.