BACKGROUND: Norovirus is one of the most prevalent pathogens causing acute gastroenteritis in children. We compared the clinical features of noroviral gastroenteritis to those of rotaviral gastroenteritis and analyzed the noroviruses' genotype frequencies. MATERIALS AND METHODS: Stool samples were obtained form 433 children hospitalized with acute gastroenteritis from May 2008 through February 2009 at Soonchunhyang University Cheonan Hospital and examined for the presence of norovirus or rotavirus. We then analyzed the clinical features of noroviral gastroenteritis in comparison with rotaviral gastroenteritis and observed the capsid protein gene sequences from the isolated norovirus for genotyping. RESULTS: Norovirus was isolated from 69 patients (16.4%) and rotavirus from 49 patients (11.6%). The noroviral gastroenteritis patients experienced vomiting (77.4%), diarrhea (73.2%), and respiratory symptoms (53.6%); the rotaviral gastroenteritis patients experienced diarrhea (71.4%), dehydration (69.3%), and vomiting (65.3%). Dehydration in patients with noroviral gastroenteritis (43.4%) was rare compared with rotavirus (69.3%) (P=0.008). The isolated norovirus belonged primarily to the GII.4 genogroup (85.5%). Our phylogenetic analysis of the GII.4 isolates revealed 3 clusters, including novel cluster C. CONCLUSIONS: Vomiting was the most common symptom in noroviral gastroenteritis patients. Dehydration in noroviral gastroenteritis patients was less common compared with rotavirus gastroenteritis patients. The majority of the norovirus strains isolated from children with acute gastroenteritis belonged to the GII.4 genogroup.