Infectious gastroenteritis is a common illness in children. This study investigated the etiology and clinical manifestations of hospitalized children with symptoms of infectious gastroenteritis in southern Taiwan. We studied 467 consecutive patients with infectious gastroenteritis aged from 2 days to 10 years hospitalized from April 2001 to March 2002. Rotavirus was the most common etiology (57%) of infectious gastroenteritis in these patients. Bacterial infection was noted in 57 cases (12%). Rotavirus was found in 92% of nosocomial infectious gastroenteritis (p < or = 0.001). Bloody stool was a presentation of bacterial infection in 74% of cases and rotavirus gastroenteritis in 8% of cases (p < or = 0.001). The G serotype of rotavirus was identified in 87 patients. Serotype G1 was the most common (51%), followed by G9 (31%). The emergence of serotype G9 strains in rotavirus infection has not been previously reported from Taiwan. Incorporation of G9 rotavirus into vaccines should be considered.