INTRODUCTION Multiple sclerosis (MS), a demyelinating disease of the central nervous system, is increasing in prevalence worldwide. Other than small-scale studies, there is a scarcity of data on the prevalence of MS in Turkey. The present study aimed to elucidate the prevalence of MS in the Middle Black Sea Region and the demographic characteristics of patients. METHODS Patients living in the Middle Black Sea Region and who were diagnosed with MS were included. The study was designed based hospital of Turkey. RESULTS A total of 1,787 patients were interviewed, and a diagnosis of MS was confirmed in 1,584. The prevalence of MS was found to be 43.2/100,000 in the Middle Black Sea Region; this was calculated based on the total population and number of patients in the provinces and districts in this region. The mean age at the disease onset was 29.39±7.6 years. Among the patients, 1,299 (81.9%) had relapsing-remitting MS, 74 had secondary progressive MS, 77 had relapsing-progressive MS, 47 had primary progressive MS, and 87 had clinically isolated syndrome. CONCLUSION The Middle Black Sea Region was found to have a high risk for the prevalence of MS. This study is the most comprehensive epidemiologic study having the largest geographical distribution on the prevalence of MS in Turkey.