A 38-year-old man was diagnosed with acute type A aortic dissection and severe aortic regurgitation, and taken immediately to the operating room for repair of the ascending aorta using the Bentall procedure. The presence of the anomalous right coronary artery was revealed at the time of the procedure, and was repaired with single coronary button technique. Some case reports have described anomalous coronary artery in association with acute myocardiac infarction or angina pectoris. This report describes a case of anomalous coronary artery diagnosed during an emergency operation for aortic dissection.