Multiple sclerosis (MS) is an inflammatory disease of central nervous system (CNS) and sexual dysfunction (SD) is one of the most common disabilities of MS women. The aim of this study was to determine sexual function of women with MS (multiple sclerosis). One hundred definite MS patients MS patients and fifty age-matched healthy controls were enrolled. Demographic data (sex, age), duration of the disease and disease pattern extracted from patient's files and Kurtzke Expanded Disability Status Scale (EDSS) recorded for each patient by an expert neurologist. Participants were asked to answer the valid and reliable Persian version of Beck depression inventory (BDI) and Female Sexual Function Index (FSFI) questionnaires. The total FSFI score and subscale scores differed significantly between the MS patients and the controls. There was a significant negative correlation between EDSS and FSFI scores (rho=-0.44, P<0.001) and significant positive correlation between EDSS and BDI (rho=0.36, P<0.001) in patients. Mean BDI and all subscales of FSFI differed significantly between patients with total FSFI score higher and lower than 26.55. Sexual dysfunction should be considered in women with multiple sclerosis.