This clinical study was undertaken to evaluate the prevalence of surgical complications of the sinus graft procedure and to set a protocol to repair sinus membrane perforations intraoperatively using a variety of techniques and materials. From January 2000 to May 2005, 338 patients were studied, on whom 474 sinus floor augmentation procedures were performed, and a total of 1166 dental implants were simultaneously placed. A total of 104 perforations of the sinus membrane were observed (19 were bilateral). In group number 1, sinus membrane perforations of <5 mm were observed in 56 sinus augmentation procedures (53.85%), 44 were treated using a resorbable collagen membrane and 12 were sutured with a resorbable material. In group number 2, 28 sinus membranes had a perforation size between 5 and 10 mm (26.92%) and were treated using lamellar bone combined with a resorbable membrane. Group number 3 consisted of 20 sinus membrane perforations>10 mm (19.23%), 10 were covered with lamellar bone combined with a buccal fat pad flap, six were treated with a mandibular block graft and four perforations were treated with only a lamellar bone sheet. Two-hundred and seventy-eight implants were placed under repaired membrane perforations and 247 implants survived. Interestingly enough, all the 25 implants that failed to integrate were placed under perforated and reconstructed membranes during the sinus lift procedure. Based on the results of this study, the survival rates of implants placed under reconstructed membranes correlate inversely with the size of the perforations.