The aim of this study was to analyze gender and age differences in physical inactivity in Croatia and physical inactivity pattern changes during the five-year period. The study is based on the data obtained from the Croatian Adult Health Cohort Study which was carried out in 2003 and 2008. The prevalence of physical inactivity in 2008 was 37.7%, 36.8% in men and 38.1% in women. In both study waves the prevalence was increasing with age in both men and women. The prevalence is statistically significantly higher in subjects older than 64 years than in younger age groups. The incidence of physical inactivity in the five-year period in total was 29.9%, 27.2% in men and 31.1% in women. The increase in prevalence of physical inactivity despite the number of preventive activities carried out periodically emphasizes the need for systematic and comprehensive approach in increasing the number of regularly physically active individuals.