The current obesity epidemic has led to a dramatic increase in insulin resistance and type 2 diabetes mellitus among adolescents, along with other obesity-related comorbidities, such as hypertension, hyperlipidemia, obstructive sleep apnea, psychosocial impairment and nonalcoholic fatty liver disease. Medical treatment of severe obesity is effective in only a small percentage of adolescent patients. In light of the potentially life-threatening complications of obesity, bariatric surgery can be considered a treatment option for adolescent patients with morbid obesity. Indications for surgery rely on both BMI and comorbidity criteria, as well as the ability of the adolescents and their family to understand and comply with perioperative protocols. The long-term effects of bariatric surgery in adolescents are not known; therefore, participation in prospective outcome studies is important. The risk associated with bariatric surgery in adolescents seems to be similar to that observed in adult patients in the short term. Data suggest that bypass procedures successfully reverse or improve abnormal glucose metabolism in the majority of patients and may be more effective in adolescents than adults. This improvement in glucose metabolism occurs before marked weight loss in patients undergoing bypass procedures, suggesting a direct effect on the hormonal control of glucose metabolism.