Solute carrier family 11 member a1 (Slc11a1), formerly known as Nramp1/Ity/Lsh/Bcg, is a proton/divalent cation antiporter that regulates susceptibility to infectious and autoimmune disease. Here we review recent studies on (1) the role of Slc11a1 in iron metabolism and iron recycling in macrophages; (2) the use of mouse breeding and introgression of knockouts onto Slc11a1 congenic backgrounds for genes encoding the multiple pleiotropic functions associated with Slc11a1; and (3) associations/linkages of SLC11A1 with human disease and how these relate to functional promoter region polymorphisms.