The Collaborative Pathology Study is one of the most impressive programs of the Bogalusa Heart Study. Attempts are made to obtain complete and uniform necropsy coverage of all decreased young people who may have been examined in the Bogalusa Heart Study. Since 1978, autopsy specimens have been collected from 190 deaths, representing 65% of all known deaths in the study age category. The relation of antemortem risk factors for cardiovascular disease to early atherosclerotic lesions in the aorta and coronary arteries was assessed in those individuals previously examined in the Bogalusa Heart Study (N = 59). Aortic fatty streaks were strongly related to both total and low-density lipoprotein (LDL) cholesterol (r = 0.62, P < 0.0001 for each association), and were inversely correlated with the ratio of high-density lipoprotein (HDL) cholesterol to LDL plus very-low-density lipoprotein (VLDL) cholesterol (r = -0.29, P < 0.01). Coronary artery fatty streaks were associated with elevated total cholesterol, LDL cholesterol, VLDL cholesterol, and systolic blood pressure. Higher levels of LDL and VLDL cholesterol, triglycerides, systolic and diastolic blood pressure, and a lower ratio of HDL to LDL plus VLDL were found in those people with coronary artery fibrous plaques. Microscopy offered additional information about the characteristics of the aortic and coronary arterial intimal disease. Histologic observations have confirmed some of the relationships indicated with gross observations and show the complexity of this disease process. These findings emphasize the importance of an approach to preventive cardiology early in life.