Despite the use of erythropoiesis-stimulating agents (ESAs), the anemia of chronic kidney disease (CKD) can be resistant to therapy. Both absolute and functional iron deficiency along with inflammation can contribute to ESA resistance and can be difficult to identify with current-day markers of iron storage. Hepcidin, a small peptide produced by the liver, is a recently discovered key regulator of iron homeostasis. Via regulation of ferroportin, hepcidin inhibits intestinal iron absorption and iron release from macrophages and hepatocytes. Because of its renal elimination and regulation by inflammation, it is possible that progressive renal insufficiency leads to altered hepcidin metabolism, subsequently affecting enteric absorption of iron and the availability of iron stores. Thus, hepcidin likely plays a major role in the anemia of CKD as well as ESA resistance. This article discusses the biologic actions and regulation of hepcidin along with reviewing studies of hepcidin in CKD.