&NA;Viral infection of the gastrointestinal tract is a major cause of morbidity and mortality worldwide, especially in underdeveloped settings. Understanding of viral structure and function, epidemiology, and host immune responses has improved rapidly as have basic science technologies (including monoclonal antibody, molecular genetic, and polymerase chain reaction techniques). Intestinal adenoviruses, astroviruses, caliciviruses, Norwalk and Norwalk‐like viruses, and atypical rotaviruses are all joining group A rotavirus as well‐described human pathogens, although rotavirus continues to be the leading cause of severe gastroenteritis in children.Current Opinion in Gastroenterology 1992,8:91‐100