Multiple sclerosis (MS) is a disease of the central nervous system (CNS) characterized by multiple regions of demyelination and inflammation along axons with a T cell-mediated autoimmune etiology. While the cytotoxic T lymphocyte antigen 4 (CTLA-4) gene seems to be a strong candidate gene in autoimmune diseases, we investigated its association with a group of patients with MS. One hundred and thirty five patients with relapsing-remitting form of MS and 135 healthy subjects were enrolled in this study. Three single nucleotide polymorphisms (SNPs) (-318C/T, +49A/G, +6230A/G) of the CTLA-4 gene were assessed using PCR-RFLP method. The genotypes -318 CC (82.9% in patients vs. 76.2% in controls) and +49 AA (31.1% in patients vs. 28.1% in controls) were overrepresented in the patient group; however, these differences were not statistically significant. In spite of some previous reports, this study did not confirm any significant association with alleles and genotypes of SNPs of the CTLA4 in Iranian MS patients. Such disparity could be due to genetic background, ethnicity and different forms of the disease.