The monograph deals with the issues of physical inactivity of children and youth, looking for possibilities to change this negative trend. Ways are searched how to draw children and youth to regular physical activity and sport, to the integration of physical activity into their lifestyle and higher quality of life. Using a questionnaire survey, authors attempted at finding out preferences of adolescents in physical activities and sports. They were also interested in opinions of pupils on the school subject P. E. & Sport as well as several problems connected with participation in the regular lessons. Pupils from elementary (59.4%) and secondary schools (52.7%) surprisingly declared physical activities and sport as the second most frequent activity during their leisure time. The time of watching television as one of the most serious sedentary activities of pupils has been decreasing with age (37 ¿ 31.3%). It was also found that the share of secondary school pupils (almost one third of boys), who devote their leisure time mainly to computer works (games, surfing on internet, social networks), has increased. The key issue here is motivation. Teachers should use motivating methods.