Abstract The sections in this article are: Physicochemical Properties of Erythropoietin Assay and Standardization of Erythropoietin Model for Kidney Production of Erythropoietin Renal Site of Production of Erythropoietin Extrarenal Erythropoietin Production Sites of Action of Erythropoietin Anemia of Renal Insufficiency Erythropoietin and Polycythemia Pharmacological Agents that Influence Erythropoietin Production Pharmacokinetics of Erythropoietin Potential Therapeutic uses of Erythropoietin Summary