The purpose of this review was to discuss the mechanism, diagnostic criteria, prevention, and clinical intervention for children and adolescents with metabolic syndrome. Metabolic syndrome is a group of risk factors which closely related to cardiovascular diseases and diabetes mellitus. Obesity, dyslipidemia, impaired glucose metabolism, and elevated blood pressure constitute the components of metabolic syndrome. Ethnicity as well as age and developmental processes have influential effects on metabolic risk factors. There is no consensus on the diagnostic criteria with worldwide acceptance for metabolic syndrome among this population. The environment for uterine fetal development, over-or under-nourishment of the pregnant mother, and over-nutrition and/or decreased physical activity in childhood may lead to the metabolic syndrome in children. Lifestyle intervention, weight loss and reduction of metabolic risk factors are recommended as prevention measures and as the main treatment goal for children and adolescents with metabolic syndrome. Although lifestyle intervention has been shown to have beneficial effects in several clinical trials, more well-designed randomized controlled trials are required in the future.