The stimulation of erythropoiesis is a rapidly evolving area of research, with mechanistic insights often developing rapidly into therapeutic agents. A broad range of erythropoiesis-stimulating agents are currently in clinical use and many more under development are likely to enter the marketplace in the near future. To date, much of the investigative activity in this field has targeted activation of the erythropoietin receptor and factors that modulate hypoxia-related pathways of erythropoietin production within cells. This Review discusses newer erythropoiesis-stimulating 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.