An oro-antral communication represents an abnormal connection between the oral cavity and the maxillary sinus. It occurs most often after tooth extractions, improper implant placement or incorrect management of the sinus lifts. Surgical repair is challenging and most practitioners usually choose the buccal advancement flap, the palatal flap and in some cases the buccal fat pad flap to close the defect. We present a 43 year-old female of a large oro-antral communication and associated chronic sinusitis which was succesfully manged by surgery. Previous interventions including 2 buccal advancement flaps, and a double layer closure using Collagen membrane and buccal advancement flap were unsuccesful. The stepwise intervention consisted on the complete cleaning of the sinus, using the Caldwell Luc technique, followed by the closure of the oro-antral communication using Bichat fat pad flap. The particular aspect was the proper integration of the buccal fat pad flap, after 3 failed attempts, without dehiscence or any other complications. The buccal fat pad flap can be succesfully used for closure of lage oro-antral communications, even when previous methods have failed and local tissue is of poor quality.