The Bogalusa Heart Study now establishes that precursors of adult cardiovascular diseases begin in childhood. The clearest evidence comes from autopsy studies that show coronary atherosclerotic lesions occur in early life and are strongly associated with very-low-density lipoprotein cholesterol, systolic and diastolic blood pressure, and obesity, and have an inverse relationship with high-density lipoprotein cholesterol. Observations of cardiovascular risk factors span a period of life from birth to 31 years of age, and longitudinal studies span a 15-year period. Risk factor variables tend to persist over time, "track." Although tracking is best for height and weight, low-density lipoprotein cholesterol and serum total cholesterol track at a high order; blood pressure tends to track at a lower order. Obesity and body fatness have an adverse influence on risk factors in children, just as noted in adults, with central obesity becoming more obvious after puberty, and having a greater adverse effect on risk factors. The emergence of abnormal levels of risk factors by adult criteria begins to occur in young adults, and is not evident in childhood. Retrospective studies, interestingly, for obesity, higher blood pressure, and dyslipidemia reveal evidence of their presence already in childhood. These findings have strong implications for undertaking prevention in early life.