Participation in daily activities within a social context (e.g. family, school, community, etc.) is essential for healthy development in adolescence. This also holds for adolescents with chronic health conditions. However, due to the requirements for treatment and due to simply being perceived as different from their healthy peers these children are often limited in many areas of everyday life. Our results showed that a considerable number of Slovak adolescents exceeded the recommended duration of screen-based activities and at the same time were not sufficiently physically active. Both were associated with negative health outcomes. Similarly, adolescents with long-term illness or chronic conditions reported higher levels of screen-based behaviour, however they did not differ from their peers, with exception of those with asthma and learning disabilities. Such children perceived barriers to active participation, including parental and personal worries, which might be associated with frequent engagement in screen-based activities. Moreover, parental restrictions as well as family joint activities were found to be important determinants of the amount of screen-time. The need of supporting a healthier and active lifestyle not only among healthy adolescents, but even more among those with health conditions is important. Intervention strategies should target their social context, including family and school, as well as the creation or increasing of a physical activity-enhancing environment. Understanding the factors contributing to active participation and the barriers perceived by healthy adolescents as well as by adolescents with health conditions is important for the development of strategies to maintain active participation and growing up healthily.