Background: Atrial fibrillation (AF) following cardiac surgery is common and has clinical impact on morbidity. The preoperative and intraoperative risk factors are still not well defined. The objective of the study was to examine preoperative and intraoperative risk factors for AF following cardiac surgery. Methods: A retrospective analysis of a database of cardiac surgeries was performed during 2017-2019 at Poriya Medical Center. Preoperative factors and intraoperative were recorded. Results: 208 patients were included in this analysis. Overall AF following cardiac surgery was detected in 50 (24%) patients. Of 175 patients who did not have history of AF prior to surgery, 27 (15.5%) had post-operative AF. In the 33 patients with previous AF, AF following surgery was detected in 23 (70%). Patients with AF following surgery who were older (66.2±8.0 vs. 60.7± 11.4 years, p=0.002), were treated more with anti-arrhythmic drugs (18.9% vs 4.5, p<0.001), and had higher rates of pre-operative AF (46% vs 6.3%, p=0.0001), prior cerebral vascular accidents (14% vs 4.4%, p=0.019), and prior valve replacement (10% vs 1.9%, p=0.009) compared to patients without AF following surgery. In multivariate Cox regression analysis, age (HR 1.04, CI 1.01-1.07, P=0.006) and history of preoperative AF (HR 6.01, CI 3.42-10.57, P<0.001) were predictors of AF following cardiac surgery. The probability of being free of postsurgical AF was 80% among patients without history of AF compared to 30% in patients with previous AF history (p<0.001). Conclusion: Preoperative AF and age were predictors of AF following cardiac surgery