Introduction: The dynamic of the rapid development in informative and media areas nowadays have changed the form of functioning in modern world. The good example for this phenomenon is Internet. Widespread access to Internet has been available only for about 20 years but its impact is clearly noticeable in almost each aspect of the life in the whole society. The children and adolescents constitute the most vulnerable group to be subject for Internet usage. The misuse of Internet might be hazardous to their somatic health and psychosocial development, including the risk of Internet addiction. Objectives: The assessment of the potential risk of Internet addiction in secondary school pupils. Methods and material: The group of 102 (43% girls, 57% boys) adolescents aged 17-19 years (mean age 18,3) assessed by the Kimberly Young’s Test and the original questionnaire. Results: There was found that 20% of examined youth meet the inclusion criteria for the risk group of Internet addiction. More then 20 hours a week being online declared 22% and the boys prevailed in this group 78% vs. 22% girls respectively. There was observed the tendency to prolong online time in spite of the previous planning, This reduced the active forms of spending leisure time and limited the direct communication within the peers’ group. The analysis of the kind of activity online revealed the differences related to sex. The boys preferred computer games 59% and visiting erotic websites 10%. Among the girls the most popular were website with music 70%, Internet searching engines 55%, auction portals 50% and chat rooms 50%. More than 30% of the respondents have suffered of somatic symptoms due to the prolonged computer usage. Conclusions: The misuse of the Internet causes the negative outcomes concerning the somatic and psychosocial aspects of the health in the adolescents. There is necessity of developing the wide media education as the tool for the prophylaxis and hazardous Internet usage by the adolescents.