Divalent metal transporter 1 (DMT1) is the first mammalian transmembrane iron transporter to be identified. In 1997, parallel experiments from two groups provided compelling evidence of its function. Fleming and colleagues identified mutations in DMT1 (formerly known as Nramp2 and DCT1) in mice and rats with defects in intestinal iron absorption and red blood cell iron utilization. Gunshin and co-workers (H Gunshin, B MacKenzie, UV Berger, Y Gunshin, MF Romero, WF Boron, S. Nussberger, JL Gollan, MA Hediger, Cloning and characterization of a mammalian proton-coupled metal-ion transporter, Nature 388 (1997) 482-488.) isolated DMT1 through an expression cloning strategy looking for mRNAs that stimulated iron uptake by Xenopus oocytes. Taken together, these data indicate that the twelve transmembrane domain protein DMT1 transfers iron across the apical surface of intestinal cells and out of transferrin cycle endosomes. Human DMT1 may be a good target for pharmacological intervention in patients with iron overload disorders attributable to increased iron absorption.