Correct growth of adolescents is one of the priorities of public health and is of special significance for the shaping of health of next generations. Recognizing and understanding health behaviours of teenagers and their determinants, as well as young people's perception of their health is the basis for programming health education and undertaking health promotion projects whose aim is shaping lifestyles promoting health. The aim of the survey was to assess the impact of pro-health activities undertaken by schools belonging to the Network of Health Promoting Schools on teenagers' lifestyle. The survey was carried out in five lower secondary and secondary schools from Tarnów and its neighbourhood, in two stages. The schools belong to Małopolska Network of Health Promoting Schools. 663 students took part in the survey, including 336 girls (51 %) and 327 boys (49%). On the basis of research and used parametric and nonparametric tests and analysis of log-car, x2 established that gender, place of residence and type of school determines health behaviours of youth. The students after three years of ·study worse of diet and devoted more time to sedentary behaviours. In generał, smoking cigarettes has increased, also frequency and quantity of smoked cigarettes. Lack of school problems dealing skills results in a nse of tobacco smoking, drinking alcohol and consumption of unheal ; thy products. Negative health behaviours are interrelated. Smoking tobacco is linked to an increased consumption of unhealthy food, as well as to a decreased and irregular physical activity.