Objective: This study was conducted to evaluate the clinical outcomes of aortic valve surgery in elderly patients and to determine the factors associated with atrial fibrillation. Methods: Between 2011 and 2015, 54 patients who underwent isolated aortic valve replacement for aortic stenosis without preoperative arrhythmia were divided into two groups: 50-69 years old (Group I; n=25) and 70 years and older (Group II; n=29). Patients’ medical records were retrospectively reviewed. Pre-, peri- and post-operation data were compared. The deaths that occurred in the first 30 days were evaluated as mortality, and the complications were evaluated as morbidity. Results: The mortality rate was found to be 9.2% (5/54) (p=0.358) in the first 30 days and 8.1% (4/49) in the first six-month follow-up, and no difference was found between the two groups (p=0.153). The following parameters were observed in Group II and were found to be statistically significant: age (p<0.01), Euroscore (p<0.01), duration of cardiopulmonary bypass (p<0.01),duration of mechanical ventilation (p<0.01), duration in intensive care unit (p<0.01), duration of hospital stay(p=0.01), acute renal failure (p=0.03), the need for dialysis (p<0.01), atrial fibrillation (p=0.04), pneumonia (p=0.03), and pleural fluid(p=0.01). We found that new-onset atrial fibrillation was associated with advanced age (p=0.02), hypertension (p=0.04), duration of cardiopulmonary bypass (p=0.03), duration of aortic cross-clamp (p<0.01), postoperative anemia (p=0.04), high creatinine values (p<0.01), and cerebrovascular events (p<0.01). Conclusion: This study showed that isolated aortic valve replacement could be performed with acceptable risks in elderly patients, and atrial fibrillation risk factors should be determined.