BACKGROUND: Liraglutide was approved for treatment of obesity in children and adolescents since 12 years. Due to gastrointestinal (GI) side effects not all patients reach maximal dose; this can affect the efficacy of obesity treatment.AIM: To study efficacy and tolerability of liraglutide in adolescents with obesity.MATERIALS AND METHODS: We analyzed medical data of adolescents with simple obesity and GI comorbidities before and in 3 months after start of liraglutide (BMI SDS; obesity complications; liraglutide side effects, and maximal doses), duration of therapy, reasons for discontinuation, and BMI SDS in 3–6 months after discontinuation.RESULTS: Liraglutide was administered for 10 adolescents (7 girls, 3 boys) 15.4 (13.5; 16.2) years with BMI SDS 3.3 (2.9; 3.7). Three months of treatment led to significant (p=0.001) decrease of BMI SDS till 2.8 (2.6; 3.5). Maximal dose of liraglutide was 3.0 mg (6 patients), 2.4 mg (2), 1.8 mg (1), and 1.2 mg (1). No correlation between maximal dose and BMI ΔSDS was detected. While dose titration patients complained of nausea (9), diarrhea (3), obstipation (1), and flatulence (1). In majority of cases complains were not dose-dependent. Only in 1 patient nausea and diarrhea that did not allow to increase liraglutide dose above 1.2 mg; additional investigation after discontinuation of therapy revealed GI infection.Therapy was discontinued in 3 months by 2 patients (1 — side effects, 1 — satisfactory result), in 4–5 months by 3 patients (1 — relapse of excessive weight gain, 2 — financial reasons), in 6 months by 1 patient (satisfactory result); 4 continued therapies. In 3–6 months after discontinuation of therapy BMI SDS increased and did not significantly differ from basal.CONCLUSION: Liraglutide is effective for treatment of obesity in adolescents and well tolerated by majority of patients. In case of pronounced adverse events additional GI investigation is recommended. Patients can discontinue treatment not only due to side effects, but also when they achieve their goal, and due to financial reasons.