The long-term outcomes of surgical ablation for atrial fibrillation (AF) during cardiac surgery remain unclear. This nationwide population-based retrospective cohort study used data from Taiwan's National Health Insurance Research Database. Overall, 11,459 patients undergoing coronary artery bypass graft, valve, or aortic surgery and diagnosed as having AF between January 1, 2001, and December 31, 2016, were included. To reduce possible selection bias, we created a propensity score-matched cohort and compared outcomes between groups. The outcomes of interest were long-term survival and late ischemic stroke. The surgical ablation group had a significantly lower risk of all-cause mortality (5.74 and 7.69 events per 100 patient-years, respectively; hazard ratio, 0.75; 95% CI, 0.69-0.81) and ischemic stroke after discharge (1.88 and 2.52 events per 100 patient-years, respectively; subdistribution hazard ratio, 0.78; 95% CI, 0.67-0.91). AF ablation performed concomitantly with coronary artery bypass graft surgery, tissue aortic valve replacement, tissue mitral valve replacement, or mitral valve repair led to significantly better long-term survival (P = .0176, P = .0001, P < .0001, P < .0001, respectively). The surgical ablation group also had better long-term survival than the matched general AF population (log-rank test, P < .001). Concomitant AF ablation during cardiac surgery is safe, does not increase the rate of perioperative complications, and confers the benefit of long-term survival after cardiac surgery in adults. AF ablation also improved cardiac surgery patients' long-term survival compared with the matched general AF population.