Purpose: The aim of this study was to compare the postoperative analgesic affects of preoperative use of a synthetic opioid tramadol and a nonsteroidal anti-inflammatory drug diclofenac sodium for postoperative pain, with placebo, in patients undergoing bimaxillary osteotomy. Patients and Methods: Thirty-six orthognathic surgery patients who underwent both Le Fort I osteotomy in the maxilla and bilateral sagittal split ramus osteotomy in the mandible as bimaxillary osteotomy were randomly allocated into 3 groups via sealed envelope technique. Group T (n = 12), group D (n = 12), and group P (n = 12) received preoperative 50 mg tramadol intramuscularly, 75 mg diclofenac sodium intramuscularly, and saline, respectively. Postoperative pain intensity (visual analog scale, verbal pain score), postoperative opioid consumption with intravenous patient-controlled analgesia, hemodynamic variables, and postoperative complications were compared among the 3 groups. Results: The median number of patient-controlled analgesia demands (n) in group P (34, 28-39) was higher than other groups (group D 14, 11-13; group T 19, 12-25; P = .001). Total tramadol consumption was higher in group P (330 mg, 290-390) compared with group D (260 mg, 190-340; P = .046) and group T (270 mg, 200-330; P = .034). The 3 groups were comparable for the area under the hemodynamic variables time curves. The area under the visual analog scale and verbal pain score curves were lower in group D and group T compared with group P, however, there was no significant difference between group T and group D. Conclusions: Preoperative diclofenac or tramadol, compared with placebo, effectively decreases postoperative opioid consumption via intravenous patient-controlled analgesia.