To determine the effectiveness of postoperative local anesthesia in tonsillectomy patients using an intra-individual study design.Thirty patients aged 5–15 were included in a prospective study. Patients received a local infiltration of 0.5% bupivacaine solution on the right tonsillar bed, and received a local infiltration of normal saline on the left tonsillar bed. Patients were asked to localize pain in terms of most disturbing side of the pharynx, on the 1st, 4th, 8th, 16th, 24th hours.Regarding pain over a 24-h period, there was a significant difference between two sides, after the 8th hour.Postoperative local bupivacaine infiltration in tonsillectomy patients was effective in children.