A systematic review and meta-analysis was performed to evaluate the effects of carvedilol versus metoprolol on the incidence of postoperative atrial fibrillation in patients undergoing coronary artery bypass grafting in randomized controlled trials. Ovid MEDLINE, PubMed, CENTRAL, and Excepta Medica (EMBASE) were searched up to March 2013 for suitable randomized controlled trials. Data were pooled using random-effects model for pairwise analyses. A total of 4 trials with 601 patients were included in this analysis. Pairwise analyses showed that compared with metoprolol, carvedilol significantly reduced the incidence of postoperative atrial fibrillation (odds ratio 0.50, 95% confidence interval 0.32 to 0.80). In conclusion, compared with metoprolol, carvedilol significantly reduces the incidence of postoperative atrial fibrillation in patients undergoing coronary artery bypass grafting.