Facilitative simple sugar uptake by mammalian cells is mediated by a family of glucose transporters. Gluts are predicted to contain 12 transmembrane domains with both amino- and carboxyl-termini located within the cytosol. The individual Gluts differ in their tissue distribution, substrate specificity, kinetic properties, and intracellular localization. These functional differences allow members of the Glut family to finely regulate whole-body glucose homeostasis.