Risk factors for death after combined valvular and coronary artery bypass graft surgery (CABG) were examined in 141 patients undergoing isolated mitral valve (MV) surgery and CABG (n = 47) or isolated aortic valve (AV) surgery and CABG (n = 94) between January 1, 1986, and January 1, 1988. Actuarial survival was 92% at 1 month and 79% at 1 year. The hazard function for death was highest immediately after operation, had a single phase of decline, and reached a low level only after about 4 months. Risk factors for death included older age at operation, preoperative hemodynamic instability, left main coronary artery disease, ischemic mitral valve disease, important tricuspid valve incompetence, and longer ischemic time. The adverse effect of hemodynamic instability at time of surgery was most pronounced in the elderly (age 70 years or more, 20% 30-day mortality). A favorable risk group includes patients under 70 years of age without left main stenosis, hemodynamic instability, or ischemic mitral valve disease; the 30-day mortality for this subset undergoing isolated valve surgery and CABG is less than 5%. A proper comparison of surgical therapy in differing patient subsets with combined valvular and coronary artery disease should include multivariate analysis in which nondichotomous variables are examined in a continuous manner rather than establishing arbitrary stratifications.