OBJECTIVE The purpose of this study was to investigate the incidence and natural history of incidentally found and untreated pulmonary embolism (PE) at coronary CT angiography after coronary artery bypass grafting. METHODS We retrospectively reviewed the records of 353 patients consecutively registered between January 1, 2010, and November 11, 2015, who underwent coronary artery bypass grafting followed within 2 weeks by coronary CT angiography. All patients received 100 mg of aspirin and 75 mg of clopidogrel after surgery. We collected relevant clinical and CT data, including total follow-up duration after coronary artery bypass grafting, follow-up CT findings, mortality, and incidence of any recurrent PE. RESULTS PE was diagnosed in 22 of the 353 patients (6.2%) who remained in the study after the exclusion criteria were applied. Most of the PEs occurred at the segmental or subsegmental level. All patients were in hemodynamically stable condition, had no symptoms, and underwent follow-up for a median of 53 months (range 19-74 months). Twenty of the 22 patients did not receive anticoagulation, and all but one of these patients had complete resolution of PE at second follow-up coronary CT angiography (median, 149 days after surgery). There was no associated mortality or recurrent PE. CONCLUSIONS Incidental PE after coronary artery bypass grafting is found in approximately 6% of patients undergoing postoperative coronary CT angiography, and most PEs resolve spontaneously without anticoagulation. No patient in this study died or had recurrent PE during a median follow-up period of 53 months.