Despite a growing number of publications on problematic Internet use (PIU), there is no consensus on the nature of the phenomenon, its constituent criteria, and its clinical threshold. This qualitative study examines the perceptions of addiction counsellors who have managed individuals with PIU in Québec (Canada). Four focus groups were conducted with 21 addictions counsellors working in public addiction rehabilitation centres. Discussion groups were digitally recorded, transcribed using a word processor, and analyzed using N'vivo 8.0 software. The results present the perceptions of counsellors regarding case management issues, including problematic applications, clinical picture, number of hours of Internet use for assessment, and for treatment.