Data on the prevalence of multiple sclerosis (MS) in Greece seem to be lacking. This study belongs to ''E group'' studies. Among 14,714 inpatients of the Department of Neurology, Athens University, during the last 20 years (1964–1983), 522 cases of MS and 258 cases of amyotrophic lateral sclerosis were detected. The prevalence of MS was then estimated at 10.2:100,000 individuals. This estimate is within the spectrum of expected values considering the geographical location of Greec