The objective of this study was to compare the analgesic efficacy of a single-dose of preoperative intravenous tramadol versus ketorolac in preventing pain after third molar surgery. Sixty-four patients undergoing elective third molar surgery were randomly assigned into one of the two groups (32 in each group): Group I received tramadol 50 mg, and Group 2 received ketorolac 30 mg intravenously preoperatively before the surgery. After injection of the study drugs, a standard intravenous sedation technique was administered and the impacted third molars were removed under local anaesthetic. The difference in postoperative pain was assessed by four primary end-points: pain intensity as measured by a 100-mm visual analogue scale hourly for 12 h, median time to rescue analgesic, postoperative acetaminophen consumption, and patient's global assessment. Throughout the 12-h investigation period, patients reported significantly lower pain intensity scores in the ketorolac versus tramadol group (P=0.05, Mann-Whitney U-test). Patients also reported significantly longer median time to rescue analgesic (9.0 h versus 7.0 h, P=0.007, log rank test), lesser postoperative acetaminophen consumption (P=0.02, Mann-Whitney U-test) and better global assessment (P=0.01, 2 test) for the ketorolac versus tramadol group. Preoperative intravenous ketorolac 30 mg is more effective than tramadol 50 mg in the prevention of postoperative dental pain.