The relationships between aortic stenosis, coronary artery disease, angina pectoris, and myocardial infarction were examined in 173 patients with isolated calcific aortic stenosis who had coronary arteriography as well as cardiac catheterization. All were over age 40 and had definite cardiac symptoms; 156 later had aortic valve replacement. Coronary lesions narrowing the lumen by 50% or more were present in 37% of patients aged 40 to 59 and 68% of those aged 60 to 82. Coronary disease was present in 64% of patients with angina pectoris and 33% of those without angina. Angina which occurred only in association with dyspnea on exertion was associated with coronary disease in 45% of instances, whereas angina which also occurred on exertion without any dyspnea or which occurred with emotional stress, after meals, during sleep, or at rest unprovoked was associated with coronary disease in 80% of instances. Patients with coronary disease without any chest pain or with atypical pain considered nonanginal were men, usually over age 60, with congestive heart failure as the predominant symptom. Electrocardiograms showing transmural inferior or anterolateral infarction nearly always indicated coronary disease, while QS patterns in Leads V1-2 occurred frequently with normal coronary arteries. Serum cholesterol was elevated in 23% of those with coronary disease and 8% of those without. A group of patients with moderate aortic stenosis could be identified, with aortic valve areas of 0.55 to 0.80 cm. per square meter, in whom coronary disease was the sole or chief cause of symptoms. The operative mortality rate with aortic valve replacement was 9.6% in those with coronary disease and 1.4% in those without significant coronary disease. Coronary disease is frequently present in patients with calcific aortic stenosis, particularly in those over 60, those with angina, and those with symptoms despite only moderate aortic stenosis. The type of anginal syndrome, the ECG evidence of transmural infarction, and the coronary risk factors provide additional clues for clinical diagnosis.