The rationale for developing a vaccine generally is made on the basis of the clinical and socioeconomical significance of a specific viral disease. The disease burden for rotavirus gastroenteritis in infants is well evaluated and several candidate vaccines for rotavirus has now been developing. An increasing recognition of the clinical significance of Norwalk virus causing acute gastroenteritis in humans of all ages, foodborne outbreaks in adults, and relatively severe gastroenteritis in children indicates that an effective vaccine would be useful. This article reviews the immunity for Norwalk virus infection and the development of a candidate vaccine for Norwalk virus.