Background: Atrial fibrillation is a common complication after coronary artery bypass grafting (CABG) surgery, although it is a benign arrhythmia it may contribute to morbidity, mortality and prolonged hospital stay. Objective: To evaluate the echocardiographic predictors of atrial fibrillation (AF) after coronary artery bypass grafting. Patients and methods: Our study was done on 100 patients who underwent CABG at National Heart Institute and Al-Azhar University hospitals from June 2020 to December 2020. Personal and medical histories were reviewed. Preoperative data included age, gender, and history of diabetes mellitus, history of hypertension and history of smoking. Intraoperative data included duration of bypass and cross clamping and number of grafts. Postoperative data included use of inotropic agents, revision of ECG during hospital stay, identification of atrial fibrillation and method of termination. Echocardiography was done during their hospital stay for assessment of the following: ejection fraction, TPASE, LV internal dimensions, LV septal and posterior wall thickness, left atrium diameter and LA Volume index, TR velocity and presence of MR. Also Pulsed wave and tissue Doppler of mitral annuli was performed to assess E/A ration, septal e', lateral e', septal E/e' and lateral E/e' and calculation of average E/e' was done. Results: Old age and history of hypertension were predictors of atrial fibrillation after CABG surgery. AF developed more frequent in patients who had used an inotropic agent after surgery and in patients with lower ejection fraction, lower TAPSE, dilated LV internal dimensions, increased LV wall thickness, and dilated left atrium and high LAVI. Our findings indicated that development of postoperative atrial fibrillation (POAF) was more frequent with higher average E/e', septal E/e', lateral E/e' velocities and lower septal e' velocity. Conclusion: Patients who had postoperative impaired LV and RV functions and increased LAVI and LA diameter experienced more frequent POAF than others. Also, higher average E/e', septal E/e', lateral E/e' and lower e' velocities were associated with higher incidence of POAF.