Postoperative pain is the most significant subjective symptom after pediatric adenotonsillectomy. The aim of this study was to evaluate the effect of postoperative analgesia exerted by peritonsillar lidocaine infiltration before tonsillectomy. A prospective double blind study was performed on 41 candidates to adenotonsillectomy (ages 7-10) for chronic or recurrent tonsillitis and chronic obstructive adenoid hypertrophy. The anesthesist prepared two syringes of 5ml: one (A) contained lidocain 2% with epinephrine (0.00125%); the other (B) contained saline 0.9% in a separate room using an aseptic technique, and was unobserved by any of the operating room personnel. Pain intensity was measured at the first, third and 24th hour after the patient's recovery from anesthesia with a visual analogue scale of 10 cm indicating "no pain" at the bottom and "worst possible pain" at the top. A significant difference between group A and group B at the postoperative first and third hours. (p < 0.01, p < 0.05) but no statistical difference after 24 h was observed. This study suggests that peritonsillar lidocaine infiltration is a potentially useful and safe method for reducing pain in the immediate postoperative period after tonsillectomy in children.