Darbepoetin alfa (rINN) (IPA: ) is a synthetic form of erythropoietin. It stimulates erythropoiesis (increases red blood cell levels) and is used to treat anemia, commonly associated with chronic renal failure and cancer chemotherapy. Darbepoetin is marketed by Amgen under the trade name Aranesp.

It was approved in September 2001 by the Food and Drug Administration for treatment of patients with chronic renal failure by intravenous or subcutaneous injection.

It is produced by recombinant DNA technology in modified Chinese hamster ovary cells. It differs from endogenous erythropoietin by containing two more N-linked oligosaccharide chains. It is an erythropoiesis stimulating 165-amino acid protein.