Continuous epidural analgesia has been used widely for chronic pain control, especially in cancer patients. As one of the complications, paraplegia developed during continuous epidural analgesia may be caused by epidural abscess, epidural hematoma, neural damage, chronic adhesive arachnoiditis, anterior spinal artery syndrome, delayed migration of extradural catheter into subdural space or subarachnoid space and preexisting disease. A 55-years-old male with lung cancer was implanted with continuous thoracic epidural catheter for pain control. Twenty days after catheterization, moderate back pain, weakness of lower extremity and urinary difficulty were developed. We suspected epidural abscess at first and made differential diagnosis with MRI which showed metastatic cancer at T2-4 spine, And compressed spinal cord was the main cause of the lower extremity paralysis.