Objectives Despite recent advances in perioperative management, postoperative atrial fibrillation/flutter (POAF) remains the most common complication after cardiac surgery. Therefore, it is important to determine related risk factors to establish effective management. However, most studies have focused on patients undergoing coronary artery bypass grafting and little is known about POAF in those who receive aortic valve replacement (AVR). We investigated the relationship of clinical predictors with POAF in patients undergoing AVR. Methods A total of 119 patients who underwent AVR were enrolled in this study, and the relationships between POAF incidence and perioperative (preoperative, operative, postoperative) factors were examined. Results POAF occurred in 47 patients (40%). In univariate analysis, older age was significantly associated with POAF occurrence, which was significantly related to prolonged intensive care unit (ICU) stay and postoperative stroke. It also showed patients with preoperative beta-blocker experienced POAF less frequently than those without beta-blocker. Multivariate analysis showed that preoperative beta-blocker usage was an independent predictor of POAF. In patients who received both preoperative oral and postoperative intravenous beta-blocker administrations, the incidence of POAF was reduced to 14% (3/22). Conclusions POAF frequently occurred in patients undergoing AVR, and was significantly related to prolonged ICU stay and postoperative stroke. Our findings show that advanced age and absence of preoperative beta-blocker usage are risk factors for POAF. Furthermore, in patients undergoing AVR, perioperative intravenous beta-blocker administration may be useful for prevention.