Cerebrospinal fluid (CSF) otorrhea following head trauma is not uncommon. Most traumatic CSF otorrhea appears immediately and ceases spontaneously. Sudden onset of CSF otorrhea owing to brain herniation into the middle ear cavity via a tegmen defect presenting many years following head trauma is rare. The paper reports a 35-year-old female who once had a major head trauma history, and after that, 13 years passed uneventfully. Sudden onset of profuse CSF otorrhea occurred to her. High resolution CT scan and MR imaging revealed a brain tissue herniated into the middle ear via a tegmen defect. Surgical repair was performed via middle cranial fossa approach. The herniated brain tissue was excised first, and the dura defect was repaired with a piece of the temporalis muscle with fascia graft which was fixed there with tissue glue. The post-operative recovery course was well, and up to now, no CSF otorrhea has recurred.