Atherosclerosis of the pulmonary arteries is a common autopsy finding and is associated with a variety of clinical conditions. To delineate the morphologic changes associated with pulmonary artery atherosclerosis, autopsies of 337 consecutive adults (greater than 15 years of age) were studied. For each, 35 features were studied, including age, coronary vascular disease, cardiac chamber hypertrophy and dilation, pulmonary artery and aortic atherosclerosis, and pulmonary thromboemboli and emphysema. These were compared using correlation coefficients and forward and backward stepwise regression procedures for selected variables. Pulmonary artery atherosclerosis correlated significantly with age, right ventricular dilation and hypertrophy, pulmonary emphysema, and aortic atherosclerosis. Regional evaluations of systemic and pulmonary atherosclerosis showed highly significant internal correlations. In the ligamentum arteriosum, the intensity of atherosclerosis over the aortic insertion correlated with the severity of a similar atheroma at the pulmonary artery insertion. With the multiple-regression procedure, pulmonary artery atherosclerosis was a significant predictor of aortic atherosclerosis, right ventricular hypertrophy, and pulmonary embolization. Our study shows that pulmonary embolization. Our study shows that pulmonary embolization. Our study shows that pulmonary artery atherosclerosis is accelerated in patients with atherosclerosis of the systemic arteries and the pathologic lesions associated with hypertensive pulmonary vascular disease.