The incidence of metabolic syndrome (MS) has increased significantly worldwide including Korea over the past decade. Recent studies have shown that the MS develops during childhood and is highly prevalent among overweight children and adolescents. Thus, it is important for physicians to be acquainted with the definition, diagnostic criteria, epidemiology, and pathophysiology of MS for early identification and management of the MS in children and adolescents, which would be helpful to decrease the burden of type 2 diabetes and cardiovascular disease in adults. The aim of this review is to provide adequate guidelines for screening and managing strategies on MS based on recent findings. Proper and effective control of MS needs close cooperation among patients, physician, family members, school, society, and government, and it should be based on a thorough evaluation of medical system on obesity and MS.