The effects of aging on erythropoiesis and the factors regulating it are not well known. Erythropoietin (Epo) is a specific growth factor for the erythroid line and is mainly produced by the kidney. As data on the effects of aging on Epo are discordant we studied serum Epo concentrations in a group of apparently healthy subjects divided into age classes in order to evaluate age-related modifications and correlations with hemoglobin (Hb) and red blood cells (RBC). Our results revealed that Epo values were correlated with age. Epo was higher in the over 65 years age classes than observed in control subjects. We believe that the elevated Epo values in the latter age class may be required to maintain Hb and RBC within normal range.