OBJECTIVES: To evaluate the prevalence of problematic mobile phone use by adolescents from public schools in a city in the state of Paraná. METHOD: The Mobile Phone Problematic Use Scale short version (MPPUS-10) was applied in adolescents of two public schools, which classifies the subject as a problematic user of a cellular device or not. For this study scores above 51 was considered problematic use; between 29 and 50 points, users at risk of becoming problematic; from 18 to 28 points were regular users and below 18, occasional users. The following variables were evaluated: age, school grade, gender, cell phone ownership, having access to other cellular devices, and their relation to MPPUS-10 score. RESULTS: Age ranged from 12 to 19 years (average: 15.5; median: 16; standard-deviation: 1.8) 420 questionnaires were given, of which only those that were correctly filled were selected, totaling 168, of which 100 (59.5%) were female. In the evaluated group, 68 (40.5%) presented a risk of becoming problematic users and 65 (38.69%) were classified as problematic users of the device. There was a positive relationship between female gender and MPPUS-10 scores. CONCLUSION: It was observed a high percentage of subjects with a tendency to become problematic users and adolescents classified as problematic users, with statistical significance between scores on MPPUS-10 and female.