Introduction: The anatomy of the paranasal sinuses is important for many surgeon groups. The precise knowledge of such structures with variable anatomy will be important for the preservation of these structures and the management of complications in surgeries such as endoscopic sinus surgery and osteotomies involving the maxilla. Objective: The purpose of the present study is to investigate volumetric differences between ethmoid, sphenoid and maxillary sinus volumes in patients with maxillary deficiency requiring Le Fort osteotomy and healthy patients, by employing computed tomography imaging. Methods: Computed tomography scans of 120 patients (59 maxillary deficiency patients and 61 control patients) were included in the study. Images were processed, the paranasal sinuses were sculpted out from 3D images and measured. All measurements were taken twice by the same observers. The observers performed the study twice with an interval of 2 weeks to detect intra-observer variability. Results: Ethmoid and left and right maxillary sinus volumes were smaller in the Le Fort group, although no differences were observed for sphenoid sinus volumes. Conclusion: Paranasal sinus volumes varied between maxillary deficiency patients and control patients. This condition may be crucial for the surgeon operating in these areas and should be taken into consideration during surgeries.