Paraplegia following spinal epidural anesthesia is extremely rare. Various lesions for neurologic complications have been documented in the literature. We report a 66-year-old female who developed paraplegia after left knee surgery for osteoarthritis under spinal epidural anesthesia. In the recovery room, paraplegia and numbness below T4 vertebra was checked. A magnetic resonance image (MRI) scan showed a spinal thoracic intradural extramedullary (IDEM) tumor. After extirpation of the tumor, the motor weakness improved to the grade of 3/5. If a neurologic deficit following spinal epidural anesthesia does not resolve, a MRI should be performed without delay to accurately diagnose the cause of the deficit and optimal treatment should be rendered for the causative lesion.