Aim <p>Unusual pneumatization of paranasal sinuses may cause extraordinary localizations of neighboring anatomic structures, thus changing the planning of endoscopic sinus surgery.</p> <p>This study aimed to evaluate the association of superior concha bullosa (SCB) with the surrounding anatomical structures and its effects on the localization of the sphenoid sinus ostium.</p> Material and Methods <p>Paranasal Computerized Tomography sections of patients who visited our institution’s otolaryngology department between 2018 and 2020 because of various complaints such as headache, nasal obstruction and smell disorder were retrospectively evaluated. Patients were divided into two groups as SCB group and control group. The association between the presence of the superior concha bullosa and the distance of the sphenoid ostium from the midline were evaluated.</p> Results <p>Total number of sinuses evaluated was 412 from 206 patients. The study cohort included 107 patients (55 males and 52 females, mean age: 33 ± 14&#xa0;years) with SCB (26 bilateral, 55 left sided, 26 right sided) and 99 patients (54 males and 45 females, mean age: 37 ± 14) without SCB on any side. The mean distance measured from the sphenoid sinus ostium to the midline was 3.98 ± 1.32&#xa0;mm in sinuses with SCB and was 3.61 ± 1.50&#xa0;mm in the SCB (-) control group (<i>p</i> = 0.006). Compared to control group, both distance of sphenoid sinus ostium from midline and frequency of lateral pneumatization of sphenoid sinus were significantly higher in patients with SCB (<i>p</i> &lt; 0.01). In terms of lateral pneumatization of sphenoid sinus; no significant difference was found between groups (<i>p</i> = 0.331). An increased incidence of rostrum pneumatization in SCB (-) sinuses were found (<i>p</i> = 0.024).</p> Conclusion <p>In patients with SCB, the sphenoid sinus ostium might be located more laterally than its expected localization.</p>