Problematic Internet Use (PIU) has of late come to the major attention of researchers of risky behaviours. For parents and teachers in turn, the various pathological forms of Internet use have become more and more noticeable. In recent years, the operationalisation of the term PIU has also been discussed and attempts to measure its various phenomena have been made. In our study, we used the quantitative method—a diagnostic survey designed on the basis of a tool of the Supreme Audit Office and Scientific and Academic Computer Network (Naukowa i Akademicka Sieć Kompureowa NASK), The survey was conducted in the first half of 2017 in Poland, among 3569 adolescents (median 16, SD = 1.28). The purpose of the research was to investigate the scale of PIU among Polish youths. For most young people, PIU is a major social problem. The majority also declare that more than half of their friends have problems with using electronic media (smartphones and the Internet in particular). On the basis of the data collected, it is estimated that 60% of adolescents use media in a functional way, whereas 40% of young electronic media users show visible PIU symptoms, of which 5% do so at a destructive level (all symptoms). Gender does not co-occur with PIU; however, family structure (where both parents are present), the setting of rules for the use of electronic media, and the place of residence are all protective factors. There is a need for constantly improved tools for measuring PIU, as well as preventive programs focused on developing self-control and helping young people understand their own emotions.