A case of central pontine myelinolysis (CPM) following rapid correction of hyponatremia is reported and a review of the literature is made. The patient was a 63-year-old non-alcoholic female who had no liver or kidney diseases in her past history. She was found unconscious after a series of convulsions and was admitted to the hospital. Eighteen months prior to admission, she had a surgery for a ruptured anterior communicating artery aneurysm. Her postoperative course was uneventful except for an urinary incontinence and mild disorientation. She was initially lethargic with conjugate deviation toward right. Nine days after admission, she still remained lethargic, and laboratory studies showed a serum sodium value of 93 mEq/l, serum osmolarity 206 mOsm/l and urine osmolarity 270 mOsm/l when she was clinically diagnosed as having SIADH. She was treated by a strict elimination of water, and administration of sodium, dexamethasone and demeclocycline. In three days, serum sodium was corrected and returned to 137 mEq/l. However, she deteriorated in consciousness and became comatose and developed quadriplegia. CT scans and cerebral angiograms were normal. One month later, another CT scans demonstrated a well-defined hypodensity area in the pons. Brain stem auditory response (BSAR) showed a prolongation of III-V interpeak latency, especially IV-V interval. Her neurological state was essentially unchanged thereafter and she died of septic shock after 12 months' hospitalization. No permission for autopsy was obtained. The clinical course, CT scans and BSAR reported here are indicative of the diagnosis of CPM.