WHO declared obesity a disease in 1979 and has named childhood obesity one of the most pervasive health challenges in the 21st century. The Danish Paediatric Society concordantly declares childhood obesity a chronic disease. Early treatment of obesity can prevent the disease from escalating into significant psychosocial and somatic complications arising in most organs with the potential to compromise normal growth and development. As argued in this review, the recognition of childhood obesity as a disease will help to increase the development of new treatment measures and health policies to prevent and manage obesity.