Objective: to determine the efficacy of lingual branch of glossopharyngeal nerve block in postoperative management of pain in pediatric patients undergoing adenotonsillectomy. methods: Prospective and cross-sectional clinical trial. the sample was 105 patients between 3 and 8 years old scheduled for adenotonsillectomy, who performed lingual branch of glossopharyngeal nerve block by anterior intraoral approach with bupivacaine 0.5% + adrenaline 1:200,000. Postoperative pain using CHEOPS scale, complications, need for postoperative analgesics, recovery time using modified Aldrete scale and time for oral tolerance was assessed. Results: We studied 101 patients classified into three groups according to the level of postoperative pain divided into mild (88.1%), moderate (7.9%) and severe (4%), with means and DS for discharged time of 50.13 ± 13.912 min, 63.75 ± 10.607 min and 86.25 ± 7.5 min; first oral intake 3.08 ± 0.829 h, 4 ± 0 h and 4 ± 0 h; and, first post-discharge pain reference of 18.3 ± 7.414 h, 5.75 ± 0.866 h and 4.5 ± 1 h respectively. Analgesic reinforcement was needed in 11.9% of the cases. there were not complications. Conclusions: Lingual branch of glossopharyngeal nerve block is a useful and effective tool in the management of pain and anesthetic recovery of pediatric patients undergoing adenotonsillectomy.