We present a case of Korsakoff's syndrome that was successfully treated with high doses of donepezil, an inhibitor of acetylcholine esterase, known to retard the progress of symptoms in Alzheimer's disease. The patient was a 46-year-old married Japanese woman who began to drink alcohol after she married. After several years of drinking she developed typical symptoms of the Korsakoff syndrome. Donepezil was started after treatment with thiamine or thiamine plus fluvoxamine had failed. Her amnestic symptoms as well as her quality of life improved markedly during donepezil treatment. Inhibition of acetylcholine esterase may be an effective treatment for Korsakoff's syndrome.