Rotavirus is a highly contagious virus, almost every child worldwide would be exposed to the virus by 5 years of age, causing acute gastroenteritis (AGE) often associated with severe dehydration and rarely even convulsion. While it is primarily transmitted via fecal–oral route by person-to-person contact, it has been postulated that spread also occurs through respiratory secretions and contaminated environmental surfaces, which can explain the rapid acquisition of anti-rotavirus antibody in the first 3 years of life regardless of hygiene and sanitary conditions. Hence based on above condition the present study was planned for Assessment of Prevalence and Outcome of Rotaviral Diarrhoea among children from Bihar Region. The present study was planned in Department of Pediatrics, Darbhanga Medical College and Hospital Darbhanga (DMCH), Bihar, India. In the present 50 childrens suffered from the children suffering from acute gastroenteritis were enrolled and evaluated. Those children admitted with acute diarrhoea their parents were interviewed for duration, fever, vomiting and any other signs of dehydration. The severity of dehydration was assessed according to the WHO Integrated Management of Childhood Illness Model Handbook guidelines and was categorized into severe, some or no dehydration. The standard proforma based on WHO protocol was prepared and used to collect all details and data. The data generated from the present study concludes that the highest incidence of rota viral diarrhea is seen in children in age group of 0-12 months. The male predominance was obtained in incidence of rota viral diarrhea during this study. All vaccinated children with rota virus vaccine were protected from rota viral infection.