Group C rotavirus was detected in stools of four patients from February to April, 1993. Of these patients, three were infants who were attendants of the day care center of the hospital. Although the route of viral infection has not been determined, the virus might have been spread within the center. Because the clinical symptoms of acute gastroenteritis caused by group C rotavirus were vomiting, serious anorexia and subsequent difficulty of oral intake of food, patients often required fluid administration therapy at the outpatient clinic. The symptoms continued 1 to 2 days. Diarrhea occurred 1.7 times daily for 1.2 days. Watery stool was found in 3 cases of patients, but no whitish stool was discovered. Vomiting developed 2.2 times daily for 1.2 days. These symptoms were less severe than those of gastroenteritis by group A rotaviral infection. The electrophoretic RNA pattern of group C rotavirus detected in the four cases were the same. However it was different from that of the virus strains previously isolated.