This study evaluated the analgesic efficacy of administering preoperatively rofecoxib or naproxen sodium to patients undergoing abdominal hysterectomy. A randomized, double-blinded prospective study was conducted with 60 women undergoing elective abdominal hysterectomy under general anesthesia. Patients were randomly allocated into one of three equally sized groups. Patients in the first group received rofecoxib 50 mg 1 h before operation (group R), patient in the second group received naproxen sodium 550 mg 1 h before surgery (group N) and patients in the third group received a placebo tablet in the same time (group P). Total amount of used morphine mixture was higher in placebo group (93+/-6 ml) than in the group R (50+/-4 ml) and group N (64+/-6 ml). There were significant difference for total amount of used morphine mixture between group P and other two groups. There was significant difference in the volumes of morphine mixture used in the first 12 h in group P and other two groups. The occurrence of side effects such as, dyspepsia, epigastric discomfort, heartburn, were similar in group R and group P. However, this side effects were increased in group N. Rofecoxib receiving preoperatively was provided clinical efficacy for postoperative pain control and well tolerated for gastrointestinal side effects comparable with naproxen sodium.