Rotavirus infections are the leading cause of severe gastroenteritis in young children worldwide. This review provides a summary of the development of a live oral rotavirus vaccine, Rotarix (GlaxoSmithKline, Rixensart, Belgium) developed from a single protective G1P[8] human strain. To attenuate the wild-type virus, the original isolate, 89-12, was passaged multiple times in tissue culture. Large safety and efficacy trials that have included more than 100,000 children around the world have shown the vaccine is safe and not associated with intussusception. The vaccine is highly immunogenic and protective against disease caused by all the most common circulating human serotypes. Efficacy against severe rotavirus gastroenteritis and hospitalization has ranged from 85-100%. Rotarix is available in the European Union, most countries in Latin America, Australia, and numerous other countries around the world. The vaccine is administered as two oral doses with at least four weeks between doses. The first dose may be administered from the age of 6 weeks, and both doses should be completed by 24 weeks of age.