During the period from February 1995 to February 1998, the epidemiology of Shigella diarrhea was studied among children less than three years of age residing in Egypt's Nile Delta. Children were visited twice a week and a stool sample was collected from any of them with diarrhea. The incidence of Shigella-associated diarrhea was 0.2 episodes/child-year, with S. flexneri being the most common serogroup isolated (55% of Shigella episodes). Younger age and the warm months increased the risk of developing Shigella-associated diarrhea, while breastfeeding was protective. Children with Shigella were ill for a mean of four days and passed a mean of six stools per day. Common symptoms included fever (35%), vomiting (19%), and dehydration (16%). Dysentery, however, was unusual, occurring in only 11% of the cases. In conclusion, Shigella-associated diarrhea remains relatively common in Egyptian children and supports the need for additional control measures including vaccine development.