The relationship between central pontine myelinolysis (CPM) and extrapontine myelinolysis (EPM) and serum sodium changes in the setting of orthotopic liver trans plantation (OLT) is examined. Postmortem examination of 14 patients with end-stage liver disease who under went liver transplantation revealed CPM in four, of which three also had EPM. A retrospective review of clinical and laboratory data was performed on all patients. There were marked perioperative rises (21–32 mEq/L) in the serum sodium concentration in all four patients who developed myelinolysis. In contrast, the largest increase in sodium in patients without demyelination was 16 mEq/L. We conclude that perioperative rises in the serum sodium concentration increase the risk of myelinolysis. CPM and EPM should be considered if the patient develops mental status changes or focal neurological deficits several days after OLT.