Obesity tracks from childhood into adulthood, and the persistence of obesity rises with age among obese children. Early onset obesity was suggested as a risk factor for morbidity and mortality later in life. In both sexes, rates of diabetes, coronary heart disease, atherosclerosis, hip fracture and gout were increased in those who were overweight as adolescents. Especially in females, obesity at late adolescence was associated with several and relevant psychosocial consequences in adulthood. Finally, a higher mortality risk for all causes of death, especially atherosclerotic cerebrovascular disease and colorectal cancer, was demonstrated in males but not in females who were overweight during high school years. Although the persistence of excess adiposity from childhood to adulthood is a morbidity risk factor, it is not known if total body fat or body fat distribution is the main factor responsible. In particular, a specific role for the intra-abdominal adipose tissue (IAAT) in childhood, independently from that of total body fat, on morbidity risk in adulthood was not demonstrated yet. The association between childhood obesity and adult morbidity and mortality strongly suggests that a more effective prevention and treatment of childhood obesity should be pursued.