The findings of an epidemiological survey of multiple sclerosis (MS) in the urban area of Catania reveal a new and in some respects original pattern of MS cases recorded on 31 December 1989 (prevalence day). They explain why special attention should be paid to patients residing in that area, which shows a remarkable upward trend of the MS prevalence rates calling for further study and for more targeted intervention in the fields of prevention, treatment and rehabilitation.