The level of fatness of a child at which morbidity acutely increases is operationally determined by calculating the body mass index (BMI). An increased risk of death from cardiovascular disease in adults has been found in subjects whose BMI had been > 75(th) percentile as adolescents. Childhood obesity seems to substantially increase the risk of subsequent morbidity whether or not obesity persists into adulthood. Among the most common sequelae of primary childhood obesity are hypertension, dyslipidaemia, back pain and psychosocial problems. Environmental/exogenous factors largely contribute to the development of body fatness early in life. Therapeutic strategies include psychological and family therapy, lifestyle/behaviour modification and nutrition education. The role of regular exercise and exercise programmes is emphasised. Surgical procedures and drugs used in adult obesity are not generally recommended in children and adolescents. Appetite suppressants and thermogenic drugs have not been approved for use in children. Digestive inhibitors such as lipase inhibitors and fat substitutes have been used in children and adolescents in off-label use and in only a few clinical studies. As obesity is the most common chronic disorder in the industrialised societies, its impact on individual lives, as well as on health economics, has to be recognised more widely. One should aim to increase public awareness of the ever increasing health burden and economic dimension of the childhood obesity epidemic that is present around the globe.