In patients with an inadequate amount of bone for implant placement, sinus lift surgery can be performed to restore a sufficient amount of alveolar bone to allow for successful implant placement and subsequent prosthetic reconstruction. In this article, the anatomy and physiology of the maxillary sinus, the mechanisms of bonegrafting, bone grafting material, preoperative evaluation, surgical technique, and the grafting procedure, as well as intraoperative bleeding and postoperative complications, are discussed. (Implant Dent 1999;8:36–46)