Background: Multiple Sclerosis (MS) is a demyelinating disorder of the Central Nervous System (CNS). In addition to the role of immune mediated mechanisms, oxidative and nitrosative stress also play an important role in neuropathology of MS. Bilirubin as an endogenous antioxidant has neuroprotective effects; however few studies have assessed the association between serum bilirubin level and MS. Objectives: To evaluate serum level of bilirubin in MS patients. Materials and Methods: Serum samples were collected from participants who referred to Kashani MS clinic in Isfahan between July 2016 and July 2017. A total of 80 MS patients (67 females and 13 males) and 94 Healthy Control subjects (HCs) (62 female and 32 male) enrolled. Compression of bilirubin levels between MS patients and HCs was done with covariance analysis. Regression analysis was used to assess the relation between bilirubin concentration and EDSS. SPSS software version 17.0 for Windows (SPSS, Chicago, IL, USA) was used. Results: The level of Direct bilirubin (Dbil) was significantly lower in MS patients compared with HCs (P=0.02). Otherwise the serum concentration of Total bilirubin (Tbil) and in Direct bilirubin (Ibil) were higher in MS patients, but it was not statistically significant. There was a negative correlation between Extended Disability Status Scale (EDSS) and bilirubin levels (Tbil, Dbil and Ibil) but it was not significant.  Conclusion: Bilirubin level is lower in MS patients and deficit of its antioxidant level may play role in neuropathology of MS.