Serological response to rotavirus and virus shedding were prospectively studied in 179 children (neonatal to 24-month-old) upon admission to a hospital during an 11-month period. Analysis of the evolution of IgG and IgM ELISA titers revealed 24 cases of rotaviral disease (serological response and diarrhea), 13 cases of asymptomatic infection (serological response and no diarrhea), 36 cases of virus carriage (absence of a serological response), three cases of past infection, and six possible cases of nosocomial infection. Rotaviral disease was encountered two out of three times and was characterized by diarrhea associated with fever and vomiting. Asymptomatic rotaviral infection and disease, observed from the neonatal period onwards, affected 2% of neonates, 20% of one- to six-month-old children, and 37% of 7-24-month-old children. In contrast, virus carriage occurred in 27%, 19%, and 14% of those children respectively. Altogether these results indicate that during the period 1-24 months of age, when asymptomatic rotaviral infection and disease were prevalent, approximately two of 10 children had rotaviral disease, one of 10 had asymptomatic infection, two of 10 were virus carriers, and five of 10 were not infected with rotavirus.