The caries experience of 11 to 12 year-old children in Scotland and Wales and 12 year-olds in England in 2008-2009: Reports of co-ordinated surveys using BASCD methodology Objective: This paper brings together summarised findings on surveys of 106,828 mainstream school pupils aged 11-12 years old undertaken in Scotland, Wales and England in 2008/09. These surveys are the latest in a series using common criteria for measurement and a range of consent arrangements which, for this age group, allow comparison between the three “countries” and over time. Method: Representative samples were drawn within the geographies of primary care organisations in the three countries and within English Local Authorities according to BASCD criteria for sampling. Consent was sought from pupils in Wales and England and passive consent was used in Scotland. Children aged twelve were examined in England and children in school year 7 (rising 12) were examined in Wales and Scotland. Examinations were conducted in schools by trained and calibrated examiners using BASCD standard criteria and caries was diagnosed at the dentinal threshold using visual criteria. Results: The trend for reducing caries prevalence and severity continues in this age group in all three countries. Unlike data for 5 year old children, the impact of seeking positive consent from pupils does not appear to have introduced bias into the results. Variation in caries levels between and within geographical areas continues. Conclusion: Caries prevalence surveys of children aged 11-12 years have been conducted across Great Britain. Those carried out with positive consent appear to produce unbiased results, comparable with previous surveys. Health inequalities in this age group persist, as does the burden of disease for those with end-stage caries. Key words: epidemiology, dental caries, prevalence, health surveys, England, Scotland, Wales, Great Britain, United Kingdom, informed consent by minors