Diarrhea is one of the most common causes of morbidity and mortality in children worldwide. Rotavirus is the most common cause of infectious diarrhea both in developed and developing countries. However, bacterial causes such as Salmonella typhi and Vibrio cholerae still play an important role in developing countries. Newly developed vaccines for rotavirus, S. typhi, and V. choleae are highly immunogenic and safe in children.