Background There are doubts among anesthesiologists on the use of the Laryngeal Mask Airway in nasal surgeries because of concerns about the occurrence of blood leakages to the airway. The primary purpose of this study on septoplasty cases was to compare Laryngeal Mask Airway-Supreme (LMA-S) and endotracheal tube (ETT) use in protecting the airway against blood leakage, as evident through the fiberoptic bronchoscopy method. The secondary purpose of the study was to evaluate oropharyngeal leakage pressure (OLP), heart rate (HR), mean arterial pressure (MAP), and postoperative adverse events.Methods The present study was conducted in a prospective, randomized, single-blind, controlled manner on 80 patients, who underwent septoplasty procedures under general anesthesia, after dividing them randomly into two groups according to the device used (LMA-S or ETT). The presence of blood in the airway (glottis/trachea, distal trachea) was analyzed with the fiberoptic bronchoscope and a four-point scale. Both groups were evaluated for OLP; HR; MAP; postoperative sore throat, nausea, and vomiting; dysphagia; and dysphonia.Results In the fiberoptic evaluation of the postoperative airway, less blood leakage was detected in both anatomic areas in the LMA-S group than in the ETT group (glottis/trachea, p = 0.004; distal trachea, p = 0.034). Sore throat was detected less frequently in the LMA-S group at a significant level in the 2nd, 6th, and 12th hours of postoperative period; however, other adverse events were similar in both groups. Hemodynamic parameters were not significantly different between the two groups.Conclusion The present findings demonstrate that the LMA-S provided more effective airway protection than the ETT in preventing blood leakage in the septoplasty procedures. We believe that the LMA-S can be used safely and as an alternative to the ETT in septoplasty cases.