Objective This paper reports the results of standardized clinical caries examinations of 5-year-old children from across England, Wales and Scotland in 2005/6. These co-ordinated surveys are the latest in a series which seek to monitor the dental health of children and to assess the delivery of dental services. Method The criteria and conventions of the British Association for the Study of Community Dentistry were used. Representative samples were drawn from participating strategic health authorities (SHAs), primary care trusts (PCTs) and health boards (HBs). Caries was diagnosed at the caries into dentine threshold using a visual method without radiography or fibre-optic transillumination. Results 239,389 five and six year-old children from across England, Wales, Scotland and the Isle of Man were examined in 2005/2006. The results again demonstrated a wide variation in disease prevalence and care strategies across Great Britain. Mean d3mft across England was 1.47 (d3t=1.l0, mt=0.20, ft=0.16), across Wales the corresponding values were 2.38 (d3t=1.70, mt=0.43, ft=0.25) and in Scotland 2.16 (d3t=1.45, mt=0.51, ft=0.20). Overall, 39.4% of children in Great Britain had evidence of caries experience in dentine (d3mft>0, including visual dentine caries). The distribution of caries was highly skewed. Thus the mean caries experience for those with dentinal decay was 3.99, as opposed to the overall mean of 1.57. Trends over time demonstrate a small change in mean d3mft since 2003/4 when the mean was 1.62, although the mean value for those with dentine decay experience remained constant (4.00 vs 3.99). The care index has also fallen marginally from 12% to 11%. The BASCD co-ordinated NHS Epidemiology Programme will evolve in coming years as differing priorities in the frequency of inspecting particular age groups is being seen as well as a desire to measure other aspects of oral health in addition. Conclusion Overall, there has been only a small overall improvement in the dental health of 5-year-old children over the last 2 years and no diminution of the level of disease in those affected for some time, although in Scotland a pattern of continuing steady progress from previously high levels is seen. While many children enjoy good oral health, sizable groups remain within the population of 5-year-old children who have a clinically significant burden of preventable dental disease. Key words: caries prevalence, dental caries, dental epidemiology, national surveys, oral health