From 1967 to 1981, 294 patients (group A) with aortic stenosis and coronary atherosclerosis underwent aortic valve replacement (AVR) combined with bypass grafting; there were 13 (4.4%) in-hospital deaths. Follow-up of the in-hospital survivors documented late survival of 89%, 79%, and 52% at 2, 5, and 10 postoperative years, respectively. Univariate and multivariate testing identified age greater than or equal to 70 years (P = 0.02) and Class IV symptoms (P = 0.002) as factors decreasing late survival. Patients with bioprostheses who did not take warfarin had the best late survival (P = 0.03) and event-free survival (P = 0.05) and patients with mechanical prostheses who did not take warfarin had the worst (P less than 0.0001) (P = 0.001). From 1981 to 1986, 375 further patients (group B) with aortic stenosis and coronary artery disease underwent AVR and bypass grafting with 20 (5.3%) in-hospital deaths. Group B contained more patients greater than or equal to 70 years (35% vs. 16%) than did group A. Logistic regression analysis identified patients with moderate or severe impairment of left ventricular function and women as sub-groups with increased in-hospital mortality in group B. Patients with aortic stenosis and coronary artery disease can undergo AVR and bypass grafting with a risk slightly increased over that for isolated AVR. Bioprostheses enhance late survival and event-free survival.