Similarity of pharmacokinetics of intranasal ketorolac to the intravenous form and other advantages have promoted its application. This study compared the analgesic effects of intravenous and intranasal ketorolac in patients undergoing mandibular fracture surgery. In this clinical trial study, Sixty-four patients with unilateral mandibular fracture were divided randomly into two groups. In group 1, 30 mg of intravenous (IV) ketorolac was injected every 8 hours and in group 2, intranasal (IN) ketorolac spray was used as a 100-µL puff in each nostril (31.5 mg) every 6 hours. After each patient regained consciousness, pain intensity was measured based on visual analogue scale for 48 hours. Finally, the total dose of the opioid analgesic agent (pethidine) and the time for the first request for an analgesic agent were recorded for each patient, and their means were compared in each group with proper statistical tests. Mean pain intensity of patients at baseline was significantly higher than that at other intervals and then, it decreased significantly (P<0.001). Furthermore, 2, 4, 6 and 8 hours after surgery, mean pain intensity in the IN group was significantly lower than that in the IV group (P<0.05). In the IN group, dose of antinociceptive medicine was slightly higher and the time to request it was shorter than the other group, but it was not statistically significant (P >0.05). Application of intranasal ketorolac spray decreased pain after mandibular fracture surgery, especially at 8-hour interval after surgery, decreasing the need for opioids.