A 37-year old man was given thoracic epidural catheter insertion for the postoperative epidural analgesia one day before the liver transplantation as a donor. During the epidural catheterization, no complications were observed. Next morning, the patient complained of postural headache and cerebrospinal fluid leakage through the catheter was noted. We concluded that the epidural catheter had migrated into a subarachnoid space and removed the catheter. On the postoperative day three, epidural blood patch was performed resulting in symptom relief. Due to the possibility of accidental subarachnoid migration of epidural catheter, careful monitoring is recommended in a patient who is undergoing continuous epidural infusion.