Extrapontine myelinolysis in the pediatric age group is very rare. We report a nine-year-old girl with the classical clinical syndrome of pontine and extrapontine myelinolysis following liver trauma due to a traffic accident. She was referred to our hospital for further investigation of convulsions due to severe postoperative hyponatremia. She had no hypoxic event or other identifiable cause for the neurological symptoms. Neurological deterioration began about two days after correction of hyponatremia and followed a period of temporary improvement in hyponatremic encephalopathy. Diagnosis of extrapontine myelinolysis was confirmed with the identification of typical features on magnetic resonance imaging. The rapid correction of hyponatremia seemed the most likely cause since other biochemical tests including liver function tests were all within normal ranges. The long term clinical outcome was good. It is important to carefully monitor the rate of correction in electrolyte disturbances, and to consider the individual variation in response to therapy.