Behçet disease is a multisystem disease, which can cause cardiovascular manifestations such as arterial occlusion or aneurysm. This report describes multidetector-row computed tomography findings of an unruptured aneurysm of the left Valsalva sinus which was associated with Behçet disease. A 45-year-old woman with Behçet disease had an aneurysm of the left Valsalva sinus which constricted the left anterior descending artery. The multidetector-row computed tomography was useful in detecting the aneurysm and complications, and was beneficial in the evaluation of patency in the coronary arteries after surgery.