In this study, we aimed to investigate the association between MS and the following four DNA polymorphisms: MTR A[2756]G, MTHFR C[677]T, MTHFR A[1298]C and MTRR A[66]G. The DNA polymorphisms were genotyped in 80 patients with confirmed MS and 80 healthy control age- and gender-matched subjects using PCR-RFLP approach.