Background: Multiple sclerosis (MS), a chronic inflammatory demyelinating disorder with neurodegenerative aspects, is more common among young adults, particularly women.Methods: This molecular study was designed to investigate the IL-7R α chain gene in Iranian MS patients. We studied 60 MS patients, diagnosed based on 2005 R-McDonald criteria and 60 apparently healthy individuals as the control group. DNA was extracted from whole blood cells using MBST/IRAN Extraction kit and all samples were screened for possible sequence variation in three regions including promoter, exon 2 and exon 4 with single strand conformation polymorphism (SSCP).Results: The alterations were confirmed with direct sequencing by ABI 3730XL. Although no mutation was detected in the studied regions, eight single nucleotide polymorphisms (SNPs) consisting of rs71617734 in promoter; rs35967524, rs11567704, rs1494558, rs11567705 and rs969128 in exon 2 as well as rs1494555 and rs2228141 in exon 4 were observed. The rs1494558 in exon 2 and rs1494555 in exon 4 were missense variations. Our results also showed the substitution of isoleucine with threonine in rs1494558 (P.I66T) with this accession number, FR863587 submitted in EMBL bank. The study of exon4 areas revealed two SNPs and two sequence variations, where [p.V138I] Valine substituted with isoleucine (FR863588), as well as a silent nucleotide substitution [P. H165H] in the absence of amino acid alteration. The analysis of the SNP genotype in the controls and the patients, using χ(2) showed no significant association with multiple sclerosis in this group.Conclusion: Our study demonstrated the effects of some SNPs on the IL-7R α protein in MS. Further studies are required to reveal the effects of these SNPs on the IL-7R α protein in multiple sclerosis.