Purpose: To compare the efficacy of the non-steroidal antiinflammatory drugs (NSAID), ketorolac and diclofenac in pre vention of pain after maxillofacial surgery. Methods: Sixty ASA I-II patients (30 in each group) received randomly, and double blindly either ketorolac 0.4 mg . kg(-1) or diclofenac 1.0 mg . kg(-1) iv after general anaesthesia induction, before surgical incision. In the ketorolac group, the same dose was repeated iv three times at six hour intervals. The diclofenac group patients received diclofenac 1.0 mg . kg(-1) after 12 hr iv. Rescue analgesic medication consisting of oxy-codone 0.03 mg . kg(-1) iv, was administered by a patient controlled analgesia apparatus. Results: Two patients in the ketorolac and three patients in the diclofenac group did not need oxycodone during the study period. On average, 12 and 11 doses of oxycodone were needed in the ketorolac and the diclofenac groups, respectively (NS). Side-effects were similar in both groups. All patients except one were satisfied with the pain therapy. Conclusion: Parenteral ketorolac (0.4 mg . kg(-1) four times in 24 hr) and diclofenac (1 mg . kg(-1) twice in 24 hr) were similar, but insufficient alone, for analgesia after maxillofacial surgery.