Thromboembolism occurs commonly in general practice and leads to significant health burden. Apart from cardiac sources, aortic atherosclerotic plaques contribute considerably to thromboembolism. A 63-year-old diabetic hypertensive woman referred to our center due to exertional chest pain unresponsive to optimal medical therapy and underwent coronary angiography. Owing to resistance during guide-wire advancement, an aortography was performed. Aortic arch injection demonstrated a large suspended mass distal to the left subclavian artery with free movement in the descending thoracic aorta. Echocardiography revealed widespread atherosclerotic changes in the aortic arch with a large hypermobile mass. Dual-source multi-slice (2 × 128:256) computed tomography angiography of the whole aorta revealed a large floating mass (in favor of a thrombus) in the distal portion of the arch. The patient underwent coronary artery bypass grafting due to severe coronary artery disease. The intra-aortic mass, which was actually a large atherosclerotic plaque, was resected at the same session. She was discharged uneventfully and during a 1-year follow-up, she had no embolic events