Post-operative atrial fibrillation (POAF) is new onset atrial fibrillation (AF) that occurs within 90 days of surgical procedure. Its underlying mechanism is believed to be related to factors such as inflammation, adrenergic surplus, infections and hypoxia. The predictors of AF recurrence in POAF population are not well defined. Establishing potential predictors of AF recurrence in POAF patients could help clinicians identify patients who are at increased risk of stroke and other complications. The aim of this study is to identify the incidence and predictors of AF recurrence after 90 days in POAF patients who have undergone cardiac surgery (CS) and non-cardiac surgery (NCS). We retrospectively reviewed the medical records of patients who underwent cardiac and non cardiac surgery at Hartford Healthcare System from January 2017 to September 2021. Surgical patients with POAF during their index surgical hospitalization were identified. Of this population patients with recurrence of atrial fibrillation after 90 days were examined. We used multivariate logistic regression to identify predictors of atrial fibrillation recurrence in these patients. Out of 81,244 surgical patients, 6,138 were CS and 75,106 were NCS. Comparing CS to NCS, prevalence of POAF was 10% vs 0.3%, average age was 71 vs 73 years, male (66% vs 53%), Caucasian (92% vs 87%). The rate of AF recurrence after 90 days in CS was 105/606 (17%) and NCS was 63/231 (27%). Predictors of AF recurrence in CS were history of heart failure (OR 2.88; 95% CI 1.53 -5.34, p<0.001) and chronic obstructive pulmonary disease (COPD, OR 5.58, 95% CI 2.77-11.3, p<0.001). In the NCS group, there was a trend towards obstructive sleep apnea and hypertension being predictive of AF recurrence, but it did not meet statistical significance. At the time of admission with recurrent AF, 66% of CS and 63% of NCS patients were on anticoagulation. Our study revealed fewer patients with POAF compared to previous reports. Furthermore, the rate of recurrence is higher in NCS compared to CS patients. Additionally, COPD and heart failure were found to be independent predictors of AF recurrence in CS patients.