Race and sex differences in aorta and coronary atherosclerotic lesions were studied in 150 persons aged 6 to 30 years. The intimal surface involvement with aorta fatty streaks was extensive, 0 to 71%, and greater in blacks than in whites (32 vs 20%, p less than 0.001). Coronary artery fatty streaks were more extensive in male than in female subjects (range 0 to 22%). Fibrous plaque lesions were present but not extensive in either the aorta (0 to 12%) or the coronary artery (0 to 24%) specimens. Lesions were more prevalent in male than in female persons, particularly white male subjects. The relation of fatty streaks to fibrous plaques was greater in the coronary vessels than in the aorta. In male subjects, aorta fatty streaks were strongly related to antemortem levels of total cholesterol, low-density lipoprotein cholesterol and ponderal index in white male subjects. Coronary artery fatty streaks in white male persons were significantly associated with serum triglycerides, very low density lipoprotein cholesterol, systolic and diastolic blood pressure and ponderal index. These results link antemortem risk factors to the development of atherosclerotic lesions and emphasize the need for preventive cardiology in early life.