OBJECTIVES: To compare the effects of preincisional peritonsillar infiltration of levobupivacaine and bupivacaine on post-tonsillectomy pain in children. METHODS: Sixty children undergoing elective tonsillectomy or adenotonsillectomy were randomly allocated into three groups before tonsillectomy: peritonsillar infiltrations with 0.25% levobupivacaine with 1:200,000 epinephrine (group levobupivacaine, n=20), 0.25% bupivacaine with 1:200,000 epinephrine (group bupivacaine, n=20), and normal saline (group saline, n=20) were applied. Pain was evaluated by using a modified Children's Hospital of Eastern Ontario Pain Scale (mCHEOPS). Choice of additional analgesic was acetaminophen for all patients. RESULTS: mCHEOPS values at 0th (immediately) and 30th minute after arrival the PACU were lower in both the local anesthetics groups than the saline group (p<0.001, p<0.01 for the group levobupivacaine; p<0.001, p<0.05 for the group bupivacaine, respectively). In addition, mCHEOPS values at 1st hour in the ward was lower in the group bupivacaine when compared to the group saline (p<0.05). Analgesic requirements and the time to first analgesia required, were also significantly different between the local anesthetic and saline groups (p<0.05 for both local anesthetics groups). Time to first mobilization was shorter in both local anesthetic groups when compared to the saline group (p<0.05 for both local anesthetic groups). CONCLUSION: Preincisional peritonsillar infiltration with levobupivacaine or bupivacaine before tonsillectomy, are effective than saline, in reducing early post-tonsillectomy pain, where as bupivacaine had slightly longer effect. Compared to saline, with both anesthetic infiltrations, lesser medication for analgesia is required. The clinical trial registration number (Research Ethics Committee of Medical Faculty, Uludag University): 2008-4/36, 19 February 2008.