Reiestad and Stromskag recently introduced the interpleural installation of local anesthetic solutions as a technique for the management of postoperative pain in patients undergoing cholecystectomy, renal surgery, and breast surgery. This study was done to manage postoperative pain in the patients undergoing unilateral upper-abdominal surgery and thoracotomy. Twenty patients received 0.5% bupivacaine 20 ml with epinephrine (Children, received 10 ml). Results were as follows: 1) Analgesic effects appeared in 15.56 minutes; mean analgesic duration from the initial intrapleural injection was 10.5 hours. 2) Blood pressure increased more after the operation than before the operation. Blood pressure before injection of bupivacaine was highest (p<0.01). Heart rate was increased before injection and 10 minutes after injection of 0.5% bupivacaine (p<0.05). 3) The values of $PaCO_2$, were improved from $41.7{pm}2.02;mmHg$ ($PaCO_2$), $85.2{pm}2.41;mmHg$ ($PaO_2$) to $37.8{pm}2.41;mmHg$ ($PaCO_2$), $107.0{pm}7.86;mmHg$ ($PaO_2$) respectively (p<0.01). 4) Complication such as pneumothorax, atelectasis and CNS toxicity did not appear. 5) Intrapleural administration of local anesthetics after unilateral upper-abdominal and thoracic surgery provided a satisfactory pain control.