Background : The long term prognostic factors of aortic valve replacement (AVR) in patients with severe aortic stenosis (AS) with normal and low left ventricular function are not well known in the Korean population. Methods : Between 1990 and 1999 , 73 patients (52 male, 21 female, mean age : 58±10.7) with severe AS underwent AVR in Yonsei Cardiovascular Hospital. Patients were excluded if they had concomitant valvular operations other than AVR, previous AVR, or more than a moderate amount aortic valve regurgitation, or were under 18 years old. Overall survival was estimated by the Kaplan-Meier method, and the Cox proportional hazards model was used to analyze the predictors that influence long-term survival. Results : The causes of aortic stenosis were degenerative (44 case, 60%), congenital (26 case, 36%), and rheumatic (3 case, 4%) in nature. The preoperative characteristics (mean±SD) included ejection fraction (EF), 58±16.5%; mean aortic pressure gradient, 63±20 mmHg ; aortic valve area, 0.62±0.13㎠. Simultaneous coronary artery bypass surgery and percutaneous transluminal coronary angioplasty were performed in 8 and 2 cases, respectively. The comparative results in all total patients of the pre/post operative echocardiography showed a significant improvement ; EF of 58±17/64±12%, aortic valve area(AVA) of 0.64±0.15/1.54±0.63 ㎠, mean pressure gradient (MPG) of 63±21/23±13 mmHg, left ventricular end-diastolic dimension (LEEDD) of 54±9/50±9 mmHg, and a left ventricular posterior wall thickness in systole (LV-PW) of 18±2/16±2 mm. The comparative results of the pre/post operative echocardiography of low EF patients (<35%) also showed a significant improvement; EF of 30±4/55±15%, AVA of 0.59±0.14/1.67±0.85 ㎠, MPG of 52±20/21±12 mmHg, LVEDD of 58±8/51±6 mm. Operative (30-day) mortality was 2.7% (2 of 73 patients). Six additional patients died during follow-up. The survival of patient group was 86% at 5 years and 78% at 10 years. The predictors of long-term postoperative survival were preop-EF (p<0.05, R=0.26) and the presence of significant coronary artery disease (CAD) (p<0.01, R=0.35). Conclusion : Postoperative long-term survival of severe AS after AVR was negatively related to reduced preop-EF and the presence of significant CAD. Therefore, the early operative treatment before the occurrence of irreversible left ventricular dysfunction and concomitant appropriate management of coronary artery disease is necessary for the improvement of the survival after AVR.