espite recent data suggesting that the rate of increase of obesity among children and adolescents has slowed and overall prevalence has possibly begun to plateau, 1,2 a worrisome trend has emerged in the form of severe pediatric obesity. As the fastest-growing subcategory of obesity in children and adolescents, 1,3,4 severe obesity afflicts between 4% and 6% of all youth in the United States 3-7 and has both immediate and long-term health consequences. Recent data further Abstract-Severe obesity afflicts between 4% and 6% of all youth in the United States, and the prevalence is increasing.Despite the serious immediate and long-term cardiovascular, metabolic, and other health consequences of severe pediatric obesity, current treatments are limited in effectiveness and lack widespread availability. Lifestyle modification/behaviorbased treatment interventions in youth with severe obesity have demonstrated modest improvement in body mass index status, but participants have generally remained severely obese and often regained weight after the conclusion of the treatment programs. The role of medical management is minimal, because only 1 medication is currently approved for the treatment of obesity in adolescents. Bariatric surgery has generally been effective in reducing body mass index and improving cardiovascular and metabolic risk factors; however, reports of long-term outcomes are few, many youth with severe obesity do not qualify for surgery, and access is limited by lack of insurance coverage. To begin to address these challenges, the purposes of this scientific statement are to (1) provide justification for and recommend a standardized definition of severe obesity in children and adolescents; (2) raise awareness of this serious and growing problem by summarizing the current literature in this area in terms of the epidemiology and trends, associated health risks (immediate and long-term), and challenges and shortcomings of currently available treatment options; and (3) highlight areas in need of future research. Innovative behavior-based treatment, minimally invasive procedures, and medications currently under development all need to be evaluated for their efficacy and safety in this group of patients with high medical and psychosocial risks. (Circulation. 2013;128:1689-1712.)