Patch closure of the orifice of an aneurysm is a common operation for sinus of Valsalva aneurysms. Recently, there have been reports of aortic valve-sparing operations for multisinus of Valsalva aneurysms. However, repair would be difficult if only one sinus of Valsalva was dilated. We report a patient with a single unruptured sinus of Valsalva aneurysm successfully treated using the patch repair technique.