Adverse drug reactions (ADR) cause significant morbidity, mortality and health costs and have an important prevalence in all ages. Few studies focus on ADR in adolescents. The goal of this study was to characterize a case series of ADR reported to the Portuguese Pharmacovigilance System (PPS) of the National Authority of Medicines and Health Products (INFARMED, I.P.) during an eleven-year period (from 2006 to 2016) concerning this specific population.Retrospective analysis of reports concerning patients from 10 to 18 years received by the PPS between 2006 and 2016. The authors evaluated patients' demographics (age and sex). The characteristics and seriousness of the reactions, the type of reaction reported, and the drugs involved were assessed.The authors found 782 reports (59% females). Most reports came from physicians (61%). Overall 80% of the reports described serious ADR. A greater proportion of serious events was found among males. Most reactions referred to general disorders and administration site conditions (38%), followed by skin and subcutaneous tissue reactions (33%). In 3rd and 4th were gastrointestinal disorders (24%) and the nervous system disorders (23%), the former more frequent among females. Vaccines were the most represented group (42%) followed by antibacterials for systemic use (19%).Major findings considering drugs involved and the reported reactions varied according to age and sex.