Autopsies on 1,150 men and 290 women following violent death were analyzed to clarify etiology of atherosclerotic lesions. Soft lesions were noted in coronary arteries in persons less than age 10 and increasingly to age 30, without significant differences between sexes. Hard lesions with more accelerated growth appeared later in life; women between ages 20 and 45 had a significant lesser amount than men. The left anterior descending coronary artery was most affected by atherosclerosis among men over age 35. High socioeconomic status, obesity, and intellectual work showed a significant association with hard atherosclerotic lesions. Neither alcohol nor smoking seemed related to atherosclerosis.