This study estimated the cost-effectiveness of infant rotavirus vaccination with Rotarix in the UK, taking into account community rotavirus infections that do not present to the healthcare system. A Markov model compared the costs and outcomes of vaccination versus no vaccination in a hypothetical birth cohort of children followed over a lifetime, from a societal perspective and the perspective of the National Health Service (NHS). The model estimated costs and quality-adjusted life-years (QALYs) lost due to death, hospitalisation, general practitioner (GP) consultation, emergency attendance and calls to NHS Direct for rotavirus infection in children aged <5 years. Time lost from work and parents' travel costs were also included in the societal perspective. The base case cost-effectiveness ratio for vaccination compared with no vaccination was pound23,298/QALY from the NHS perspective and pound11,459 from the societal perspective. In sensitivity analysis, the most important parameters were hospitalisation cost and number of GP consultations. Addition of Rotarix to the paediatric vaccination schedule would be a cost-effective policy option in the UK at the threshold range ( pound20,000-30,000/QALY) currently adopted by the National Institute for Health and Clinical Excellence.