Background. Familiarity with the anatomy of the arteries in the sinus wall is essential to prevent the perforation of the sinus membrane and bleeding during dental implant surgery.Objectives. The aim of the study was to evaluate the anatomical position of the posterior superior alveolar artery (PSAA), using cone-beam computed tomography (CBCT). Material and methods.A total of 245 CBCT scans met the eligibility criteria for this cross-sectional study. The vertical distance from the lower border of the artery to the lower border of the sinus floor, the diameter of the artery, and the type of artery (intrasinusoidal, intraosseous or superficial) in the first and second premolar and molar regions were measured. The data was analyzed with the t tests, the one-way analysis of variance (ANOVA) and the χ 2 tests.Results. The maxillary PSAA was recognized in 187 (76.3%) scans. The mean distance between the artery and the floor of the sinus was 6.87 ±3.68 mm. The mean diameter of the artery was 1.37 ±0.61 mm. The greatest mean diameter of the artery was observed in the second premolar region, and the smallest in the first molar region. As many as 63.6% of the arteries were intraosseous, 28.9% intrasinusoidal, and 7.5% superficial. Conclusions.Due to the high prevalence of the intraosseous type, in most cases of sinus lift surgery there is an increased possibility of PSAA damage. As the largest diameter of the artery was observed in the second premolar region, the possibility of severe bleeding during sinus lift surgery in this area is increased. The average distance between the artery and the floor of the sinus was approx. 7 mm. Consequently, it is recommended that the lower border of the sinus access window should be as high as 7 mm to the floor of the sinus.