The elevated risk for thromboembolic events in cancer patients has been well documented. Chemotherapy is considered to be one of the most important risk factors for cardiovascular complications such as arrhythmias, cardiomyopathy, angina, and myocardial infarction. However, acute aortic thrombosis is an extremely rare complication in patients receiving chemotherapy. The authors report a case of acute aortic thrombosis after adjuvant capecitabine chemotherapy for colon cancer.