The rotaviral antigen was detected by a screening test using the ELISA-IC kit in 17.6% out of 415 children with acute gastroenteritis. The highest frequency (28.9%) was found in children hospitalized in pediatric services with a diagnosis of diarrhoeic disease associated to acute respiratory infection. The rotavirus infection incidence was about three times higher during the cold season than during summer (30.4% versus 10.5%). The 6-11 month age group was the most severely affected.