Background: Surgical treatment of symptomatic atrial fibrillation has been performed for 3 decades. We reviewed trends and outcomes of surgical ablation (SA) for stand-alone atrial fibrillation using The Society of Thoracic Surgeons Adult Cardiac Surgical Database (STS-ACSD). Methods: The STS-ACSD was reviewed from 2011 to 2017 (N = 7187) for trends. Contemporary data from 2014 to 2017 (n = 3893) were used to compare three subgroups: off pump (n = 3252), on pump (n = 491), and patients with incision conversion or conversion from off pump to on pump (n = 150). Propensity score matching was conducted to balance groups. Results: Annual growth of stand-alone SA was 7%. Median age of patients was 64 years (interquartile range, 57 to 70), and 30% were female. Overall 30-day mortality was 0.8% and perioperative stroke incidence was 0.8%. Most SA procedures were off pump (84%), with 12% greater odds for off pump per year (odds ratio [OR] 1.12, P <.001). The off-pump group had fewer biatrial SA (21% vs 71%, P <.001) and left atrial appendage obliterations (53% vs 95%, P <.001) compared with the on-pump group. After matching, uneventful off-pump SA had similar mortality (0.4% vs 0.9%, P =.292) vs on-pump SA, but reduced incidence of renal failure (0.9% vs 2%, P =.033). After risk adjustment, the conversion group had worse perioperative outcomes vs the off-pump group, including greater incidence of stroke (OR 5.37, P <.001) and operative mortality (OR 9.98, P <.001). Mortality (OR 4.69, P =.011) was also greater for conversion vs on pump. Conclusions: Steady growth of stand-alone SA operations was noted. Procedures performed either on pump or off pump were relatively safe. However, intraoperative conversion was associated with significantly higher morbidity and mortality. Patient selection, improvement of surgical techniques, and long-term follow-up should be emphasized to improve decision making and outcome.