Background: Surgical indications in patients with severe chronic aortic regurgitation (AR) and normal left ventricular (LV) ejection fraction (EF) remain to be established, especially in terms of LV dilation. Methods: Pre-operative clinical and echocardiographic characteristics were evaluated in 308 consecutive patients with chronic severe AR who underwent aortic valve surgery. Pre-operative LV EF was normal (���50%) in 180 patients (group A), and was depressed (<50%) in 128 patients (group B). Mortality was observed for a median of 39.3 months. Results: Of 308 patients, 11 (6.1%), and 19 (14.8%) died after aortic valve surgery during follow-up period in group A and group B, respectively (p=0.018). Pre-operative LV end-systolic dimensions (LVDs, 42.6짹7.5 vs. 56.0짹10.8 mm, p<0.001) and end-diastolic dimensions (64.9짹8.1 vs. 72.8짹10.2 mm, p<0.001) were significantly lower in group A than group B. Of 180 patients in group A, only 10 patients (5.6%) and 18 (10.0%) showed LVDs ��� 55 mm and LV end-diastolic dimension ��� 75 mm, respectively. By multivariate Cox regression analysis in group A, age [hazard ratio (HR): 1.091, 95% confidence interval (CI): 1.010 - 1.179, p=0.027], concomitant coronary bypass surgery (HR: 9.417, 95% CI: 1.532 – 57.867, p=0.015), pre-operative LVDs (HR: 1.287 per 1 mm, 95% CI: 1.109 – 1.493, p=0.001), and hemoglobin level (HR: 0.564, 95% CI: 0.362 – 0.878, p=0.011) were independent predictors for mortality after surgery, whereas presence of pre-operative symptom was not. LVDs ��� 40 mm and hemoglobin ��� 13.7 g/dL were best cutoff values for post-operative mortality by ROC curve analyses. Conclusions: Pre-operative LVDs seems to be an independent prognostic factor after aortic valve surgery in patients with chronic severe AR and normal LV EF. However, the optimal cutoff value warranting surgery might be lower than 55 mm in such patients.