Objectives: To evaluate the changes in the pharyngeal airway space (PAS) before and after bi-lateral sagittal split osteotomy (BSSO) surgery using a three-dimensional cone-beam computed tomography (3D-CBCT). Material and Methods:The sample consisted of patients (n=7), aged between 21-30 years, having a skeletal Class II with retrognathic mandible and orthognathic maxilla who underwent orthodontic treatment and were advised for BSSO advancement surgery. Pre-surgical CBCT scans were taken a week before the surgery (T0) and the post-treatment records, three months after the surgery (T1). The 3D PAS was reconstructed from the CBCT scans, and the volumetric changes were evaluated.