Aim of the study:
The dangers resulting from the dysfunctional use of mobile phones by adolescents are presented in the study. The main aim of the conducted study was the exploration of addiction to mobile phones used by secondary students as well as the presentation of differences in addiction to mobile phones in group of women and men. 470 Polish secondary students from Silesia took part in the study.

Subject or material and methods:
The author’s distributed questionnaire which contained questions concerning the types of the Internet activity, the aims and intensity of use of modern means of communication (computers with the Internet access and the mobile phones) and the Survey form and the Mobile Phone Addiction Assessment Questionnaire (KBUTK) by Potembska and Pawłowska were used in the study.

Results:
The criteria of being at risk of mobile phone addiction were fulfilled by about 35% of tested students and about 4% of students were addicted to mobile phones. Analyzing the level of addiction to mobile phones by gender, it can be stated that more women than men fulfill the criteria of being addicted and being at risk of addiction to mobile phones.

Discussion:
The obtained results proved the hypothesis formulated in the study which assumed that there are statistically significant differences between the students who correctly and pathologically use mobile phones in total and by gender.

Conclusions:
The problematic use of mobile phones by the adolescents may be a cause of health problems and social expense.