Postoperative cognitive dysfunction is a common geriatric complication that may be associated with increased mortality. Here, we investigated the effects of postoperative analgesia with ketoprofen on cognitive functions in aged animals and compared its effectiveness to morphine. Rats were randomly allocated to one of four groups: isoflurane anesthesia without surgery (group C), isoflurane anesthesia with laparotomy (group IL), and isoflurane anesthesia with laparotomy plus postoperative analgesia with ketoprofen or morphine. There was no difference in postoperative locomotor activity among groups. In group IL, postoperative pain levels assessed by the Rat Grimace Scale significantly increased until 8 h after surgery, which was similarly inhibited by both ketoprofen and morphine. Cognitive function was assessed using radial arm maze testing for 12 consecutive days from postoperative day 3. Results showed that the number of memory errors in group IL were significantly higher than those in goup C. However, both ketoprofen and morphine could attenuate the increase in memory errors following surgery to a similar degree. Conversely, ketoprofen showed no effect on cognitive function in the nonsurgical rats that did not experience pain. Our findings suggest that postoperative analgesia with ketoprofen can prevent the development of surgery-associated memory deficits via its pain-relieving effects.