Haase VH. Hypoxic regulation of erythropoiesis and iron metabolism. Am J Physiol Renal Physiol 299: F1-F13, 2010. First published May 5, 2010; doi: 10.1152/ajprenal.00174.2010.-The kidney is a highly sensitive oxygen sensor and plays a central role in mediating the hypoxic induction of red blood cell production. Efforts to understand the molecular basis of oxygen-regulated erythropoiesis have led to the identification of erythropoietin (EPO), which is essential for normal erythropoiesis and to the purification of hypoxia-inducible factor (HIF), the transcription factor that regulates EPO synthesis and mediates cellular adaptation to hypoxia. Recent insights into the molecular mechanisms that control and integrate cellular and systemic erythropoiesis-promoting hypoxia responses and their potential as a therapeutic target for the treatment of renal anemia are discussed in this review.