We sought to evaluate the efficacy of ropivacaine in post-tonsillectomy pain management in adults and evaluate the timing of intraoperative ropivacaine administration for this purpose. A prospective, double-blinded, randomized, controlled trial with a paired design was performed in 25 consecutive adults undergoing tonsillectomy. To date, no studies examining the efficacy of local anesthetics in post-tonsillectomy pain control have used a paired design to account for the variability in pain difference between individuals. Patients were prerandomized into those receiving tonsillar fossa injections before or after the tonsillectomy. All surgeries were performed by the senior author. The tonsil on 1 side was injected with saline and the tonsil on the other side with ropivacaine. Patient responses were obtained via written questionnaire. Three of 25 patients were excluded from the study. Sixteen of 22 patients had lateralization of pain to 1 side during recovery. No statistically significant difference in pain control was observed between ropivacaine and normal saline. Local anesthetic decreased pain in 7 of 22 patients, and increased pain was experienced on the side with local anesthetic in 9 of 22 patients. Six of 22 patients had no difference in pain from one side to the other. The time to equalization of pain based on laterality was 8.8 and 6.8 days, respectively, in the patients injected before or immediately after the tonsillectomy. Administration of the local anesthetic ropivacaine does not affect post-tonsillectomy pain. Moreover, timing of injection does not affect postoperative pain. We recommend against the use of intraoperative ropivacaine for pain control in patients undergoing tonsillectomy.