The authors report two cases of hepatic encephalopathy with chronic hepatic failure. Case 1 was a 78-year-old woman with liver cirrhosis, admitted because of general fatigue and loss of appetite. Her electroencephalogram showed frequent slow waves in the theta range with intermittent triphasic waves T1-weighted MR images showed increased signal intensity in the globus pallidus and the putamen. Case 2 was a 71-year-old woman with chronic hepatitis, admitted because of depression. Her electroencephalogram showed frequent slow wave activities in the theta-delta range with intermittent trisphasic waves. Her serum ammonia level was 84 micrograms/dl (normal 12-54 micrograms/dl). T1-weighted MR images showed increased signal intensity in the globus pallidus, the putamen and the hypothalamus. On the basis of these findings, both patients were diagnosed as having hepatic encephalopathy, although disturbance of consciousness was not obvious. The observed MR image abnormalities might be due to the metabolic and pathological changes of chronic hepatic failure. Such MRI findings may be useful for the diagnosis of hepatic encephalopathy.