To be useful, a screening program depends on an acceptable, valid, and reliable test, and an efficacious and cost-effective intervention in the population of interest. Screening children to detect those at high risk of adult hypertension or hypercholesterolemia was examined from this viewpoint. Long-term studies starting in childhood have so far revealed less than optimal validity of blood pressure and serum cholesterol levels in childhood as predictors of adult levels. However, information was sparse regarding reliability of measurements, accounting for which could improve validity. The efficacy of interventions that could be widely applied in childhood had not yet been demonstrated. In addition, the costs of an extensive screening program and risks such as misclassification, side effects, and labeling needed to be evaluated. The results of this study helped determine whether screening for risk factors in childhood was a useful method for preventing cardiovascular disease in adults.