A seven-year-old, 25-kg female crossbreed dog received segmental thoracic epidural anaesthesia for left lateral thoracotomy and lung lobectomy. At presentation mild exercise intolerance and weight loss were reported. A chest CT scan revealed a solitary soft tissue mass in the left caudal lobe. Lung lobectomy surgery was scheduled. Under isoflurane anaesthesia, an epidural catheter was threaded through T13–L1 and advanced 50 mm cranially. Bupivacaine and morphine were administered 30 minutes before incision and at 12-hour intervals thereafter. To minimise side effects, the postoperative dose was titrated to guarantee segmental analgesia. Purposeful movements and signs of sympathetic stimulation in response to surgery were not observed. Intraoperatively, a transient 13% increase in arterial blood pressure occurred, while heart rate remained stable compared with baseline. Although the intended postoperative dose was decreased to prevent side effects, pain scores were below the analgesic intervention score. The catheter was removed on the fourth postoperative day. Complications and neurological sequelae were not noticed.