Thiamine deficiency is known to lead to certain neurologic sequales including Wernicke-Korsakoff syndrome. Wernicke's encephalapathy is charac-terized by ataxia, ophthalmoplegia, nystagmus, and mental change. Although classically associated with chronic alcoholism, a number of other predisposing conditions exist such as hyperemesis gravidarum, thyrotoxicosis, starvation, anorexia nervosa, prolonged total parenteral nutrition, gastric plication and renal dialysis. We have experienced a case of Wernicke's encephalopathy associated with prolonged starvation which was misdiagnosed by hyponatremic ence-phalopathy at first, and which seemed to be developed by thiamine-free dextrose infusion in 39-year-old male patient. We report the case with review of the literature and emphasize the need for thiamine supplementation with slow correction of hyponatremia before the infusion of dextrose solution in the prolonged starved hyponatremic patient.