Background: Excellent outcomes after aortic valve replacement (AVR) in elderly patients can be achieved, yet some practitioners are reticent to refer elderly patients for surgery. This study analyzed risk factors for mortality in patients aged 80 years and older undergoing AVR with or without concomitant coronary artery bypass grafting (CABG). Methods: A retrospective review was performed of 245 patients (129 women) with a mean age of 83.6 ± 2.9 years who had AVR with (n = 140) or without CABG (n = 105) at a single institution from 1993 to 2005. Data were analyzed with a multivariate logistic regression for predictors of operative mortality, Kaplan-Meier estimates of survival, and a Cox multivariate proportional analysis of factors influencing long-term survival. Results: Mean preoperative New York Heart Association (NYHA) classification was 3.1 ± 0.9, and 78% (192/245) of patients were classified as NYHA class III or IV. Operative (30-day) mortality was 9% (22/245). Independent risk factors for operative mortality included postoperative renal failure (odds ratio [OR], 20.9; 95% confidence interval [CI], 6.5 to 67.6; p < 0.001), postoperative permanent stroke (OR, 11.3; 95% CI, 1.7 to 75.1; p = 0.019), or intraoperative/postoperative intraaortic balloon pump (IABP) placement (OR, 14.9; 95% CI 2.9 to 75.8; p = 0.002). Survival after surgery was 82% (n = 183) at 1 year and 56% (n = 88) at 5 years. Prognostic factors for decreased long-term survival were regurgitant valve pathology (hazard ratio [HR], 6.0; 95% CI, 2.5 to 14.2; p = 0.002), intraoperative/postoperative IABP (HR, 2.9; 95% CI, 1.4 to 6.0; p = 0.010), postoperative renal failure (HR, 3.5, 95% CI, 2.2 to 5.7; p < 0.001), and postoperative stroke (HR, 7.0, 95% CI, 3.2 to 15.9; p < 0.001). Performing concomitant CABG was protective in terms of operative mortality (OR, 0.3; 95% CI, 0.09 to 0.83; p = 0.017) and improved long-term survival (HR, 0.7, 95% CI, 0.47 to 0.96; p = 0.020). Preoperative NYHA classification did not affect operative or long-term survival. Conclusions: Patients aged 80 years and older who undergo AVR have acceptable short-term and long-term survival regardless of NYHA status. Concomitant CABG improved operative and long-term survival in this population. Despite their increased age, aggressive surgical treatment is warranted for most patients.