Epidemic viral gastroenteritis is a significant world wide problem. In developed countries, gastroenteritis accounts for significant morbidity and loss of time from work; in the Third World it is the leading cause of mortality among infants and children. Recent technologic advances have been associated with an explosion of research activity. Two virus groups, the Norwalk-like agents and the rotaviruses, are currently accepted as causative agents of viral gastroenteritis in man. The problem of viral gastroenteritis is reviewed both from a current and a historic perspective.