This study compared the effectiveness of flexible laryngeal mask (F-LMA) insertion and endotracheal intubation in pediatric patients undergoing adenotonsillectomy surgery. A total of 60 patients aged 2-12 years were included in the study. Patients were divided into the F-LMA group (n=30) and endotracheal tube (ETT) group (n=30). The groups were compared according to intubation time, heart rate, SpO2, EtCO2, airway pressure, surgical field of view, and recovery time. Both the insertion time and recovery time were shorter in the F-LMA group than in the ETT group (16.93±4.84 s vs. 23.93±8.74 s; and 10±2 min vs. 14.5±3 min; p