This report reviews the risks and consequences associated with childhood and adolescent obesity. Although no consensus definition of childhood obesity exists, the various measures encountered in the literature are moderately well correlated. The paper is organized in three parts. The first section reviews childhood obesity sequelae that occur during childhood. These short-term risks, for orthopedic, neurological, pulmonary, gasteroenterological, and endocrine conditions, although largely limited to severely overweight children, are becoming more common as the prevalence of severe overweight rises. The social burden of pediatric obesity, especially during middle childhood and adolescence, may have lasting effects on self-esteem, body image and economic mobility. The second section examines the intermediate consequences, such as the development of cardiovascular risk factors and persistence of obesity into adulthood. These mid-range effects of early obesity presage later adult disease and premature mortality. In the final section, the small body of research on the long-term morbidity and mortality associated with childhood obesity is reviewed. These studies suggest that risk of cardiovascular disease and all-cause mortality is elevated among those who were overweight during childhood. The high prevalence and dramatic secular trend toward increasing childhood obesity suggest that without aggressive approaches to prevention and treatment, the attendant health and social consequences will be both substantial and long-lasting.