An approach to the treatment of post-operative pain by the injection of bupivacaine into the pleural space through an intrapleural cathter has been studied. Among 24 thoracotomy patients, bupivacaine was injected only to experimental group[ 12 patients ] when the patient was able to head up for oneself during recovery from anesthesia. The pain and ROM[ range of motion ] scores, respiration rate, PaCO2 level of both experimental and control group were measured at the time of head-up and 30 and 120 minutes thereafter.The scores of pain and ROM of experimental group were significantly[ P value < 0.05 ] decreased in 30 minutes and 120 minutes after bupivacaine injection compared with those of control group but respiration rate and PaCO2 level were not changed significantly. With this result, we can suggest that intrapleural injection of bupivacaine is useful for pain relief following thoracotomy.