The prevalence of significant coronary artery disease (reduction in luminal diameter by more than 50%) among 88 consecutive patients with aortic stenosis requiring aortic valve replacement at Hammersmith Hospital was examined. Twenty two (34%) patients had significant coronary disease. Nineteen of 42 (45%) patients with typical angina had coronary disease; three of 20 (15%) patients with atypical chest pain had coronary disease, while none of 26 patients free of chest pain had significant coronary disease. Risk factors for coronary disease were equally distributed among patients with and without significant luminal obstruction. Because of the small, but definite, hazard of coronary arteriography and in the interest of cost containment it is suggested that patients with aortic stenosis who are free of chest pain do not require routine coronary arteriography. This applies particularly to patients requiring urgent aortic valve replacement.