Background: Existing smoking prevalence comparisons between the ‘old’ and ‘new’ members of the European Union (EU) give a misleading picture because of differences in methodology. A major EU project designed to find ways of closing the health gap between the member states, included the first ever comparison of smoking prevalence between these countries using a methodology that minimises potential biases. Methods: A detailed analysis of methods and data from the most recent nationwide studies was conducted in the adult population of 27 countries of the European Union and Russia as an external comparator. To maximise comparability, daily smoking in the age range 20-64 was used. Prevalence of current daily smoking, former smoking and never smoking were age-standardised and calculated separately for males and females. Findings: The European map of smoking prevalence shows that male smoking prevalence is much higher in the new than the old members of the EU, whereas in females the reverse is true, but there are also very large differences in smoking rates between particular countries within the same region. Sweden clearly has the lowest prevalence, and the prevalence in the United Kingdom (UK) at the time of the surveys emerges as near the average for old-Europe but higher than, for example, Ireland. Interpretation: Restricting the analysis to daily smokers aged 20-64 produces a map of Europe in which variation in prevalence between individual countries within regions is as important as variation across regions. Survey methods need to be harmonised across countries to enable comparisons involving all ages and non-daily as well as daily smokers.