Background: The aim of this study was to assess the patterns of socio-economic inequalities in leisure-time physical activity (LTPA) in the different member states of the European Union. Methods: Comparable data on subjects aged 16-64 years derived from national health interview surveys from 15 European countries were used for the analysis. We used log-binominal regression to assess prevalence rate ratios (PRRs). The PRR measured the risk of showing a low level of LTPA for a given educational level, relative to the highest educational group. Results: Within Europe, large cross-national differences in the overall prevalence of a low level of LTPA were observed. However, a low level of LTPA was always more common among those of lower educational attainment. The educational inequalities in a low level of LTPA were more pronounced in men. For the lowest compared with the highest educational level, the PRR was 1.53 (95% CI: 1.49-1.57) in males and 1.36 (95% CI: 1.33-1.39) in females. There was no consistent relationship between the absolute level of prevalence rate, as measured by the rate for the highly educated, and the magnitude of these inequalities. Conclusions: Throughout Europe, physical activity during leisure time is less common among the lower educational groups compared with the higher educational groups. Programs to promote LTPA should consider strategies that target people of lower educational attainment.