Abstract Uric acid (UA) is a hydrophilic antioxidant product associated with multiple sclerosis (MS). We conducted a randomized case-control study to evaluate the serum level of UA in different phases of MS in comparison with levels in a healthy control population. Serum UA was checked in 130 patients with relapsing-remitting MS (85 patients in remitting and 45 patients in relapsing phase) and 50 age-matched controls using a quantitative enzyme-linked immunosorbent assay (ELISA). The mean concentrations of UA in serum was 6.41(±3.18) mg/dL in patients with remitting MS, 4.76(±1.66) mg/dL in patients with relapsing MS and 6.33(±2.94) mg/dL in controls. There was a significant difference between mean UA concentration in relapsing MS and remitting MS ( p < 0.001), and between patients with relapsing MS and controls ( p = 0.002); however, the difference between levels for patients in the remitting phase of MS and the control group was not significant ( p = 0.87). It seems probable that UA has a role in the prevention of disease activity in MS.