A floating thrombus in an apparently normal aortic arch is a rare and often neglected source for systemic embolic events. When no other underlying pathology for systemic embolization can be found, transesophageal echo (TEE) and magnetic resonance imaging (MRI) are the diagnostic methods of choice and should be performed in order to detect thrombus formations in the thoracic aorta. We report a case in which a floating thrombus in the aortic arch was the source of emboli into both femoral arteries. Successful bilateral thrombectomy was performed. To prevent repeat embolization, we performed surgery under deep hypothermic circulatory arrest with removal of the thrombus and plication of the aortic wall at the site of thrombus adhesion.