Alcoy is a defined health region in eastern Spain, at 3 degrees E-38 degrees N, with a single neurology department and includes 33 towns with a total population of 133,915 inhabitants. We have evaluated the prevalence and incidence of multiple sclerosis (MS) by analysing this region. Six new cases have been detected (2.24/100,000/year) and the prevalence rate was 17.17/100,000, the highest in Spain at the moment. However, we found an irregular distribution in the different towns in so far that 15 of our 23 patients lived in a particular subregion, which means a prevalence of 44.59/100,000. Our study shows that the area of Alcoy is a medium MS risk region according to the thesis of Kurzke, although high MS areas may be found, thus confirming that MS distribution in southern Europe is not uniform.