One cannot practice pediatrics in the tropics without being impressed by the frequency of infection with intestinal parasites. These infections are widely prevalent on the Isthmus of Panama where instead of being chiefly of academic interest as they are in most of the United States, they are of prime clinical importance. Excellent contributions to the knowledge of helminthiasis have appeared in the literature. These detailed accounts, however, have been devoted more to biologic than to clinical aspects, particularly as the latter relate to children. The discussions devoted to symptoms, physical findings and treatment have been brief, confusing, and frequently not borne out by observation. These existing misconceptions concerning the incidence, clinical manifestations and treatment of intestinal helminthiasis in children prompted this survey. Source Material This study deals with 518 children infected with intestinal parasites who were admitted to the pediatric wards of Gorgas Hospital, Ancon, Canal Zone from January 1, 1941 to January 1, 1944.