Epidural analgesia, via either a thoracic or lumbar route, is commonly used to provide postoperative analgesia following thoracotomy for pulmonary resection, but little data indicate which location is better in terms of postoperative analgesia, side effects, or associated complications. In this study, 45 patients, who were scheduled to have epidural analgesia and undergo a lateral thoracotomy, were randomized to receive either a thoracic or a lumbar catheter. Pain assessments and routine clinical data were recorded to determine if either thoracic or lumbar epidural catheters provided superior analgesia, fewer side effects, or fewer complications. This study found no statistical difference in pain relief or side effects between lumbar and thoracic epidural analgesia for post-thoracotomy pain. An increased infusion rate (6.4 +/- 1.9 v 5.1 +/- 1.4 mL/h, P = 0.02) was required in the lumbar group to achieve equivalent analgesic levels.