Morphine, a $mu$-receptor agonist, produces strong analgesic effect with some side effects such as nausea, vomiting, urinary retension, somnolence, and respiratory depression. Buprenorphine also provides strong analgesic effects, and hemodynamic changes after continuous infusion of morphine, or buprenorphine-ketorolac combination in gynecologic patients. Analgesic effect was assessed by visual analogue scale(VAS) and Prince Henry scale(PHS). Morphine group, initial 2 mg of bolus morphine was followed by 48 mg/96 ml of continuous infusion. Buprenorphine group, initial 0.1 mg of buprenorphine was followed up with infusion by 2.3 mg/100 ml. Half dose of both initial bolus and maintenance buprenorphine with ketorolac 15 mg for bolus and 60 mg for maintenance were infused in buprenorphine-ketorolac combination group. No significant hemodynamic changes were seen in any of the groups. VAS significantly decreased after 15 minutes of infusion in all three groups, and was significantly lower in morphine group than the other 2 groups, after 60 minutes. PHS was decreased significantly 15 minutes after infusion in the morphine group, and after 60 minutes in two other groups. The incidence of side effects were similar between morphine and buprenorphine groups, but significantly reduced in buprenorphine-ketorolac combination group. We concluded that buprenorphine could be an alternative to morphine for postoperative pain, and smaller dose of buprenorphine could be used if it is combined with ketorolac with less side effects.