There are a number of techniques available for performing sinus augmentation surgery, which has been reported to be a highly predictable procedure. The osteotome-assisted sinus augmentation procedure is a technique that enables simultaneous placement of implants in the atrophic maxilla. Carefully following specific steps as described in this article results in clinical success. Using the OASA technique, the size of the incision and reflection of the periosteal flap are minimized and the lateral window is reduced, thereby decreasing the removal of bone from the lateral sinus wall and the potential for postoperative complications, such as swelling and pain.