Anemia has been linked to increased mortality and morbidity in renal hemodialysis patients. Other risk factors that contribute to an adverse outcome include the variability of hemoglobin (Hb) levels and the decreased response to erythropoiesis-stimulating factors (ESFs). In this study we evaluated the effectiveness of four different ESFs (epoetin-A, epoetin-B, darbepoetin, and CERA), assessed the variability of Hb levels, and compared ESF dosages which contributed to the achievement of Hb levels in each individual patient with renal failure undergoing chronic hemodialysis maintenance. In conclusion, the four ESFs administered are equally effective in the treatment of anemia in renal hemodialysis patients and they do not influence in a different manner the variability of Hb. The administration of darbepoetin-A and CERA might possibly cause more patients to overshoot the target level of Hb.