In valve-sparing operations for aortic root aneurysms, the dilated aortic root is replaced by a vascular graft. However, cusp disorders remain in some cases. We observed closed cusps endoscopically, and an improvement in the cusp coaptation was seen following plication. One of our cases of aortic valve plication is reported here. A rigid thoracoscope and cannula for cardioplegia delivery were inserted from the distal end of the aortic graft, and the graft was inflated with cardioplegic solution, providing an endoscopic view of the closed aortic cusps. We believe that endoscopic observation of closing cusps in this way may help surgeons to learn and master the techniques used in cusp repair more rapidly.