A wide range of erythropoiesis-stimulating agents to stimulate red blood cell production are currently in clinical use, but advances in our understanding of erythropoiesis have provided an ever-increasing array of potential therapeutic targets. Here, Robert Foley describes the desirable properties of erythropoiesis-stimulating agents and discusses various novel agents currently under assessment for the treatment of anemia in patients with chronic kidney disease. Such agents include proteins and peptides that activate erythropoietin receptors, non-protein agents, and strategies with targets other than erythropoietin receptors.