Anemia is a common and debilitating condition in patients with chronic kidney disease and patients with cancer. Over the last 10 to 15 years, the introduction of erythropoietic therapy has transformed the management of anemia in both these conditions. The first therapeutic agent to be used for the stimulation of erythropoiesis was recombinant human erythropoietin (epoetin). At the turn of this century, darbepoetin alfa, a second-generation erythropoietic agent, became available. Darbepoetin alfa contains two additional N-linked carbohydrate chains, which confer greater metabolic stability in vivo. More recently, a third-generation molecule, Continuous Erythropoietin Receptor Activator (CERA), incorporating a large polymer chain, has been developed. CERA has an elimination half-life in humans that is considerably longer than the half-life of either epoetin or darbepoetin alfa. CERA may also have different receptor binding characteristics and pharmacology from other erythropoietic agents; these characteristics are the subject of ongoing investigation. CERA is currently in phase III clinical trials.