Childhood obesity is perhaps the most significant public health problem in the most developed countries and is rapidly becoming so in developing countries. National Health and Nutrition Examination Survey data shows a 3-fold increase in the prevalence of obesity in childhood, over past few decades. Furthermore, childhood obesity has markedly contributed to the prevalence of the metabolic syndrome and type 2 diabetes in U.S. children. Alarmingly, there is increasing evidence that atherosclerosis develops silently during childhood in obese children. In the Bogalusa Heart Study, pediatric autopsy studies showed a clear relationship between the number and severity of risk factors, principally obesity, with atherosclerosis in both the aorta and coronary arteries. Increased intimal medial thickness (IMT) was not present among obese adults who had been normal weight as children, emphasizing the cumulative effects of childhood obesity persisting into adulthood. Thus, the need for primary prevention of cardiovascular disease beginning in childhood is strongly suggested.