Since aortic calcification is seen on X-rays of the prelumbar region in many patients, its relation with cardiovascular disease (CVD) was investigated in a prospective study in The Netherlands. X-rays were taken of 1359 men and 1598 women, in 1975-78. In the subsequent 9 years, 50 men and 33 women died from CVD. The prevalence of aortic calcification was about 10% in middle-aged subjects and rose with age to a maximum of 45% in men and 75% in women. Aortic calcification was associated with a six-fold increased risk of CVD death in men aged 45 years, independent of major CVD risk factors. For each year of age over 45, risk associated with the presence of aortic calcification declined by 6%. Death rates in middle-aged women were too small for risk analysis. These results suggest that atherosclerosis in other than coronary or cerebral vessels may have predictive relevance for CVD death: its diagnosis indicates intervention on present CVD risk factors.