Background & Objectives : Multiple Sclerosis is a chronic progressive disease with several disabilities for patients. Its distribution in the world can be an important clue to study racial, genetic, and environmental factors; thus, epidemiologic studies have been a very attractive concept for recent papers.

  Methods: We conducted this retrospective study to determine the prevalence of multiple sclerosis in different geographic areas of Fars (south of Iran). We first evaluated 11 large cities for the prevalence of the disease. In the second stage, we searched for five clinical subtypes of the disease (relapsing remitting, clinical isolated syndrome, progressive relapsing, primary progressive and secondary progressive) in both men and women.

  Results : From 2535 patients, 523 (20.6%) were men and 2012 (79.4%) were women. The prevalence of the disease in the total population of Fars was 54.3 / 100,000. Shiraz had the highest and Firoozabad had the lowest number of patients for each sex. The most common clinical subtype was relapsing remitting in each city, as well. The female-male ratio was 3.8 / 1.

  Conclusion: Fars is a medium to high risk area for multiple sclerosis and women are affected more than men. The most common clinical subtype of multiple sclerosis is relapsing remitting (71%) followed by clinical isolated syndrome (22%).