Background: Intrathecal injection of morphine is widely used in the management of postoperative pain because it provides long-lasting analgesia. Intramuscular caroverine and tiaprofenate are used to produce postoperative pain relief. This study was designed to evaluate the analgesic efficacy and quality of sleep achieved with intrathecal morphine and those of intramuscular caroverine and tiaprofenate in transurethral resection of the prostate (TURP). Methods: Forty patients undergoing elective TURP were randomly allocated into 2 groups as follows: Group M (n=20); 0.25 mg of morphine hydrochloride mixed in 7.5 mg of 0.5% hyperbaric bupivacaine was administered at the time of induction of spinal anesthesia. Group S (n=20); 7.5 mg of 0.5% hyperbaric bupivacaine was administered intrathecally and caroverine and tiaprofenate intramuscularly at every 8 hr and 12hr postoperatively for management of postoperative pain. We evaluated the analgesic efficacy with visual analog scale (VAS), quality of sleep, and side effects. Results: VAS at 6, 12 and 24 hours after operation were significantly less (p<0.01) in the group M than in the group S. Group M was superior to group S with respect to quality of sleep (p<0.01). In the group M, the incidence of nausea was 30% (6/20) and that of pruritus was 35% (7/20) and clinical respiratory depression did not occur. Conclusions: Intrathecal 0.25 mg morphine provides good postoperative analgesic effect. but intramuscular caroverine and tiaprofenate does not.