Objectives: This study sought to investigate the positioning of the posterior superior alveolar artery in relation to the performance of the maxillary sinus bone graft procedure in a Korean population. Materials and Methods: We identified the position of the posterior superior alveolar artery relative to 93 maxillary sinuses in 58 patients and determined the distance from the inferior border of the artery in the premolar and molar areas to the alveolar ridge and sinus floor. Results: The mean distance from the alveolar ridge to the posterior superior alveolar artery in the dentate group ($20.62{pm}3.05mm$ in the premolar region, $17.50{pm}2.84mm$ in the molar region) was greater than as compared to the edentulous group ($18.83{pm}2.79mm$ in the premolar region, $15.50{pm}1.64mm$ in the molar region), and this difference was statistically significant (P<0.05). In contrast, there was no statistically significant difference (P>0.05) between the mean distance from the sinus floor to the posterior superior alveolar artery in the dentate group ($8.21{pm}2.79mm$ in the premolar region, $7.52{pm}2.07mm$ in the molar region) or in the edentulous group ($7.75{pm}3.31mm$ in the premolar region, $7.97{pm}2.31mm$ in the molar region). Conclusion: Prior to surgery, it is important to evaluate the position of the posterior superior maxillary artery by using computed tomography scans. The premolar area is safer than the molar area for performing the maxillary sinus bone graft without bleeding.