Extrahepatic portal-systemic encephalopathy due to congenital extrahepatic portosystemic shunt has so far been rarely reported in the literature. We herein report 3 such cases without liver cirrhosis or portal hypertension which were presented with the chief complaint being disturbance of consciousness and abnormal behavior. In all cases the brain computed tomography scan revealed no pathological findings, while electroencephalogram showed a diffuse slow activity with triphasic waves. The laboratory data revealed a high serum ammonia level. Percutaneous transhepatic portography demonstrated portosystemic shunts. After these shunts were surgically occluded, the serum ammonia level reached a normal range and encephalopathy disappeared. A liver biopsy also revealed neither fibrosis nor cirrhosis in any of the cases. The 23 previously reported cases are also discussed.