One of the current recurrent priority topics in public health, in Europe and North America in particular, is that of increasing overweight and obesity. The prevalence of both conditions is increasing, adversely affecting population health, daily living and life expectancy, and placing an increasing burden on health services. Well to the forefront in this concern about obesity is concern about obesity in children - both because of the direct affect on children’s health, but also because of the future problems this will cause for individuals and society. This is so much a concern that in 2006 the European Regional Office of the World Health Organisation hosted a Ministerial Conference on Counteracting Obesity, for the Health Ministers of all countries in the region (WHO Regional Office for Europe, 2007). All countries in Europe are thus aware of, and committed to addressing, this modern public health challenge. However, action needs evidence. This requires firstly, an understanding of the problem, including its causation and dynamics, prior to considering how to tackle it. Second, it requires quantification or the problem’s causes as well as manifestations, and that presents challenges for an issue as dispersed and interspersed in societal activity and personal behaviour as is the case with obesity. When focussing on children, the problem is even more challenging, given the problems of gathering data about children, and given the multiple and changing influences and decision-makers in their lives in the span from infancy to adolescence. That is where the Scientific Platform project of the EU Working Party on Information on Lifestyle and Special Population groups comes into effect. Its task in the year 2007 has been to ascertain the availability of data at national level in EU Member State, Applicant State, and European Economic Area nations. And to enable that work to be undertaken, a baseline analysis of the aspects to be measured in terms of lifestyle determinants was undertaken on behalf of the project partners by the Centre for Health Planning and Management, Keele University. This publication seeks to share that knowledge and current evidence on measurement issues in childhood obesity determinants for a wider readership.