Background: A mural thrombus in the descending thoracic aorta frequently leads to distal organ and acute limb ischemia, increasing overall morbidity and mortality. Early diagnosis is imperative as thrombi are usually discovered after end organ damage has taken place. The formation of a mural thrombus in descending aorta has not been fully explained; however, the principle of Virchow's triad for thrombogenesis (hypercoagulability, stasis of blood flow and endothelial injury) remains the likely pathophysiologic mechanism. Case Presentation: We present a case of a descending aortic thrombus incidentally detected on computed tomography scan in a 65-year-old female and successfully treated with anticoagulation, preventing subsequent complications. Conclusions: Suspicion for an aortic thrombus should arise when the origin is not known for acute onset distal limb or organ ischemia.