Computers have become one of the most popular devices around the globe. Undeniably it has a lot of profits, nevertheless, vast number of drawbacks can be observed. Thanks to computers the time of various tasks and activities has bee shortened, but simultaneously, the number of health discomforts among the internet users has increased. During the research it has been released that internet addicts had similar symptoms to gamblers. The aim of this project is to estimate the rate of teenagers’ internet addiction. The modified questionnaire of a survey by Kimberly Young was used in this project as a research tool. After a written agreement of a headmaster and respondents, the study was conducted in the High School. The subjects of the research were 127 students, including 85 boys (67%) and respectively 42 girls (33%). 65% of respondents (n=83) live in a countryside, while the remaining group 35% /(=44) are settled in small towns (up to 20 000 citizens). Conclusions: It has been revealed that 1/5 of the surveyed has problems with controlled internet usage. What is more, it has been shown that the internet has a negative influence on peers’ contact, housework duties and wise free time usage. Moreover, the abusive usage of internet leads to depression and aggressive behaviour. Vast majority of the interviewees had some health discomforts due to prolonged internet usage.