Glycogen storage disease type III (GSD III) was found in the past with an unusual frequency among North African Jews in Israel. The aim of this study was to review the long-term clinical course of GSD III's patients in Israel. Relevant pediatric and adult clinical units of all Israeli hospitals were approached to report on their GSD III patients. 21 (14 M/7F) live patients were located. The average age of the patients was nearly twenty years. Eleven patients were older than 18 years of age. 76% of the patients were of Jewish North African origin, 14% of Jewish European origin, and 10% were Arab Muslims. The symptoms at presentation were fasting, hypoglycemia, hepatomegaly slight hypotonia in infancy and delayed growth. Although in most of the patients their signs and symptoms ameliorated after childhood, significant complications were observed in some 20% of the patients. Consequently, a life long follow up of GSD-III patients is required.