In the article "An Epidemiologic Approach to Multiple Sclerosis," by Dr. John F. Kurtzke, published in the February issue of the Archives, the following corrections should be made. On page 214, right-hand column, the sentence starting five lines from the bottom should read "The prevalence rate is higher the longer the duration of illness." In the footnotes to Tables 5, 6, 7, and 8 the word "prevalance" should be changed to "probability" in each instance.