In this article the Authors describe a procedure aimed to restore under endoscopic control, the continuity, of the Schneiderian membrane (SM) incidentally teared during a sinus lift with transcrestal approach.In a 44-year-old male, due to aforementioned complication, the SM was gently detached via transcrestal approach, with a customized small ball burnisher, in order to facilitate the placement of a collagen sponge, to close the communication with the sinus, followed by the subsequent insertion of a graft material. All the procedure was endoscopically controlled and, considering the successful grafted area elevation, was simultaneously followed by implant placement. After 6 months the second stage was performed always under endoscopic control.The endoscopic view of the grafted area showed a dome-shaped elevation sited on the top of the implant, the SM was apparently normal with no signs of inflammation, the antrum was empty and normally functioning. Periapical X-rays were performed: immediately after the surgery; at both 14 days and 6 months post-operative; at 6 months post prosthetic finalization. The volume of the grafted area progressively decreased over the time while its radiopacity, on the contrary, gradually increased, as expected after graft integration and remodelling. The implant was submitted to no functional load for 4 months by means of a temporary screwable acrylic crown inserted on a peek abutment and then finalized with a cementable metal-ceramic crown on a preformed titanium abutment.The Authors recommend the use of endoscope to repair the SM incidentally teared during transcrestal sinus lift.