Background: There is evidence that the prevalence of common mental disorders varies across Europe. Aims: To compare prevalence of common mental disorders in general practice attendees in six European countries. Method: Unselected attendees to general practices in the UK, Spain, Portugal, Slovenia, Estonia and The Netherlands were assessed for major depression, panic syndrome and other anxiety syndrome. Prevalence of DSM-IV major depression, other anxiety syndrome and panic syndrome was compared between the UK and other countries after taking account of differences in demographic factors and practice consultation rates. Results: Prevalence was estimated in 2344 men and 4865 women. The highest prevalence for all disorders occurred in the UK and Spain, and lowest in Slovenia and The Netherlands. Men aged 30-50 and women aged 18-30 had the highest prevalence of major depression; men aged 40-60 had the highest prevalence of anxiety, and men and women aged 40-50 had the highest prevalence of panic syndrome. Demographic factors accounted for the variance between the UK and Spain but otherwise had little impact on the significance of observed country differences. Conclusions: These results add to the evidence for real differences between European countries in prevalence of psychological disorders and show that the burden of care on general practitioners varies markedly between countries.