OBJECTIVE. In children aged less than 10 years, to assess whether adenotonsillectomy has some permanent or transitory effect on middle ear pressure. MATERIAL AND METHODS. 20 children aged 4 to 9 years old (13 girls and 7 boys) participated in the study. The day before surgery and on days 1, 7, 14 and 21 after adenotonsillectomy both tympanometry and pure tone audiometry were performed. During surgery, medication consisted in dexamethasone, atropine, propofol and sevoflurane. RESULTS. Before surgery, the middle ear pressure was within the range of 0 ± 99 daPa. On day 1 of the followup study, the average right and left middle ear pressure decreased less than -99 daPa in 6 patients aged 4 to 9 years old (2 girls and 4 boys), with a body mass index from 11.9 to 16.6. At day 7 of follow-up, the middle ear pressure increased and none of the patients showed a pressure less than -99 daPa. Before surgery and during the 21 days of follow-up, hearing thresholds were always ≤ 20 dB nHL. No significant difference was observed between children with or without an average middle ear pressure lower than -99 daPa on their age, weight, height, body mass index or duration of the surgery. CONCLUSIONS. After adenotonsillectomy, children aged 4 to 9 years old who received dexamethasone, atropine and sevoflurane might develop negative middle ear pressure with no hearing loss, which may resolve in 1 week. After adenotonsillectomy, in patients with otalgia or risk factors for middle ear disease, closer evaluation of middle ear pressure may be advisable.