Abstract: Erythropoietin (EPO) is a glycoprotein hormone secreted by humankidney cells. Human EPO was induced from human embryo kidney cells, isolated and pu-rified from medium by biochemical method in our laboratory. The hypoproliferative ane-mia in chronic renal failure (CRF) has been assumed to be the result of decreased EPOproduction by the damaged kidney and of the shortening of the survival of erythrocytes. In this study, CRF anemia was formed 9 weeks atter the removal of five-sixths of therenal mass of rats. These anemic rats were divided into 6 groups: treated with differentdosages of EPO or physiological saline. The results indicate that EPO has apparent effects on anemia in rats with CRF. Itmay stimulate erythropoiesis and improve the anemia state of rats with CRF.Hemalotogical parameters (RBC, Hb, PLT, Ht and Rt )may be reverted to normal levels(P<0.001 ). The level of BUN and Cr were significantly decreased. The optimum doseof EPO was 1000 U/kg. All these results show that injection of EPO has therapeutic ef-fect on anemia in rats with CRF. EPO showed no effect on normal rats.