Erythropoietin (EPO) is a glycoprotein synthesized in the kidneys which regulates the rate of proliferation and differentiation of red blood cell precursors. The main cause of anemia in children with chronic renal failure is deficiency of EPO production as a result of declining renal function. Recombinant human EPO (rHuEPO) is a synthetic erythropoietin that is structurally and functionally similar to naturally occuring EPO. Treatment of anemia using rHuEPO has been associated with an improvement in the quality of life for patients, likely attributable to an increased production in hemoglobin and a reduction of dilatation of the heart. Recently, an analogue of EPO with two extra oligosaccharide chins, darbepoetin alfa, has been described as having a more prolonged effect requiring less frequent dosing.