Solute carrier 11a1 (SLC11A1; formerly NRAMP1, where NRAMP stands for natural resistance-associated macrophage protein) is a proton/bivalent cation antiporter that localizes to late endosomes/lysosomes. SLC11A1 regulates macrophage functions that are of potential importance in the induction and/or maintenance of autoimmune diseases such as rheumatoid arthritis, type I diabetes and Crohn's disease. We investigated SLC11A1 gene as a candidate gene for genetic susceptibility to multiple sclerosis (MS) in our population. Four SLC11A1 gene polymorphisms (5'GT repeat, D543N, 1729 + 55del4 and 1729 + 271del4) were analysed in a case-control study of 195 patients with MS and 125 control subjects. We found no evidence of association between SLC11A1 polymorphisms and MS susceptibility in the Spanish population.