This trial will determine the population effectiveness of Rotarix in Bangladeshi infants. The study will be conducted in both the government comparison area and the intervention area of the Matlab HDSS. To carry out the evaluation, we will introduce the Rotarix vaccine into half of the villages of the HDSS area. In villages randomized to receive Rotarix, the study will be explained to parents and if they consent to their child's participation and the child is eligible, the child will receive two doses of Rotarix during their first two EPI visits (scheduled for 6 and 10 weeks of age), if possible, as would routinely be done if Rotarix were included in the government programme. Administration of Rotarix will be conducted by regular EPI staff, but ICDDR,B study staff will be present to document informed consent and collect study-specific information. Vaccination with Rotarix will be recorded on the infant's immunization card which is normally used by the EPI programme, but also on a separate study-specific data collection form. Participation in the study will not affect a subject's receipt of other routine childhood immunizations or other medical care. In villages randomized not to receive Rotarix, children will receive their EPI vaccinations exactly as they would have in the absence of this study.