The aim of the study was to evaluate the benefit of cone beam computed tomography (CBCT) and how to minimize injury to the posterior superior alveolar artery (PSAA) before sinus lift procedure. Cone beam computed tomography scans of 30 maxillary sinuses (15 patients) assessed to determine the location of PSAA presinus lift procedure. The data collected were used to extend the existed literature. The most common location of the PSAA was intraosseous (66.7%), the subantral distance mean was 5 ± 1 mm, and the mean distance of PSAA from the crest was 15 ± 1.6 mm. Cone beam computed tomography is valuable before the sinus lift procedure to exclude the presence of any lesion and to detect the location of the PSAA. The study recommends not to extend the upper border of the window beyond 16 mm from the residual crest during the lateral sinus approach.