OBJECTIVE Aortic insufficiency (AI) associated with ascending aneurysm can be corrected by valve-sparing aortic root reconstruction ('David' reimplantation, 'Yacoub' remodeling). Intraoperative endoscopic evaluation in the aortic root may help to clarify the procedure and to access competence of the preserved valve. METHODS Following cross-clamping of the ascending aorta, an endoscopy was inserted into the proximal aortic root. Perfusion of crystalloid cardioplegia enabled the visualization of the pressure-loaded valve in the closed position. Conventional macroscopic evaluation would have overlooked valve prolapse because of a release from perfusion pressure. Valve coaptation was imaged directly before and after the valve-sparing procedure. A total of 17 patients underwent aortic root reconstruction under endoscopic guidance. Indications of the valve-sparing were determined with endoscopic findings. The degree of AI before and after the surgery was evaluated by aortography and scored (0, none; 1 trivial; 2, mild; 3, moderate; 4, severe). RESULTS Remodeling was employed to eight patients and reimplantation to four. The other five patients were replaced with prosthetic valved-conduit. There was no early and late mortality. Before and after the valve-sparing surgery, grades of AI were significantly reduced. Three patients who underwent reimplantation procedure required late valve replacement for late progression of AI, however, none of the patients with remodeling required reoperation. CONCLUSIONS Introduction of an endoscopy successfully reduced postoperative AI and clarified indications and limitations of valve-sparing aortic root operations.