Severe obesity (body mass index>120% of BMI IOTF-30 cut off) and morbid obesity (BMI>140% of BMI IOTF-30 cut off) affect 5 to 10% of obese adolescents in France. Organic complications can be found in about 50% of these patients, and depressive symptoms in one-third of them. Finally, over 70% will suffer from adult morbid obesity associated with a marked increase in morbidity and mortality. However, the reversion of obesity strongly decreases, and may even cancels, these risks. In controlled randomized studies, lifestyle interventions have limited effectiveness on BMI in children (and none in adolescents). Bariatric surgery has been shown to have short-term effectiveness in adolescents with severe and morbid obesity: the average BMI loss after gastric banding was 11.6kg/m2 (95% confidence interval from 9.8 to 13.4), 16.6kg/m2 (95% confidence interval from 13.4 to 19.8) after bypass, and 14.1kg/m2 (95% confidence interval 10.8 to 17.5) after sleeve gastrectomy. The resolution of comorbidities was the main aim, as well as the improvement of quality of life. This is not a simple surgical intervention, and minor side effects have been reported in approximately 10–15% of teenagers who underwent surgery (more common with the gastric band), and severe side effects in nearly 1–5% (mainly with bypass). In France, recommendations regarding indications, the care pathway, multidisciplinary meetings, reference management structures and postoperative care have been published by the French National Health Authority (HAS) in 2016 to provide a framework for bariatric surgery in underage patients.