To establish the implication of Rotavirus in acute diarrhea of babies and children. Prospective study on 164 patients aged between 1 month and 3 years with acute diarrhea, admitted in the Clinical Hospital of Infectious Diseases Iaşi between 01.01.2005 - 31.03.2005. Rotavirus cause the illness in 30 patients (18.29%). The disease was more prevalent among children with dystrophy or with other comorbidities like: iron-deficiency anemia, intestinal parasitosis, rhinopharyngitis, pneumococcal meningitidis. In seven cases the infectious was considered to be nosocomial. During the illness patients also accused other symptoms, while in order of frequency were: common respiratory infection (13.3%), nausea and vomiting (40%), maculopapular eruption and intestinal pneumonia (16.6%), acute pharyngitis (10%). In this study latex agglutination confirmed the diagnosis. Vomiting and diarrhea led in all cases to moderate or severe dehydration. Appropriate rehydration was necessary but only in 12 cases was made through intravenous access with: Ringer lactate, isotonic sodium chloride solutions. Most children recovered with in 5 days.