Atherosclerosis is a generalized process that may involve the entire vasculature as well as the coronary arteries. Aortic atherosclerosis (AA) is associated with an increased risk for recurrent ischemic stroke and cardiovascular death and can be diagnosed by transesophageal echocardiography (TEE). We performed TEE in 60 patients (47 men and 13 women; age range 37-78, mean 53.5 +/- 9.9) who underwent coronary angiography, to assess whether atherosclerosis in the thoracic aorta correlates with coronary artery disease (CAD) or may be a marker for it. Significant CAD was defined as either > 50% reduction of internal diameter of the left main coronary artery or > 70% reduction of the internal diameter in the anterior descending, right coronary or circumflex artery. The number of diseased vessels was based on the Coronary Artery Surgery Study criteria. A grading system was used to detect AA. The thoracic aorta was considered to be normal and classified as grade I when the internal surface was smooth and without lumen irregularities or increased echo-intensity. Grade II changes consisted of increased echodensity of the intima without lumen irregularity or thickening. Grade LII changes consisted of increased echodensity of intima with well defined atheroma extending < 3 mm in the aorta. Grade IV and V changes consisted of atheroma > 3 mm and protruding mobile plaques, respectively. Grades III-V were considered as AA. Twenty two of the 29 patients (75.9%) with CAD and 10 of the 31 patients (32.3%) without CAD had AA detected by TEE. There was a significant relationship between CAD and AA. (r = 0.44, p < 0.001). The sensitivity and specificity of AA in detecting CAD were 75.9% and 67.7%, respectively. Our data suggest that AA is common in patients with significant CAD. Detection of AA by TEE may be a marker for CAD and early detection of aortic atherosclerosis may contribute to diagnostic and therapeutic interventions and thereby improve the prognosis.