Splenopneumopexy, which was developed in Japan, has been recognized as an effective surgical procedure in patients with Budd-Chiari syndrome. We report the case of a 72-year-old woman with Budd-Chiari syndrome and prominent hepatic encephalopathy. She was treated by splenopneumopexy 19 years previously at our institute. Recently, during a follow-up visit, she experienced disorientation and unconsciousness. Flapping tremor was also recognized, and electroencephalography demonstrated a triphasic wave. In computed tomography and angiography imagings, the inferior vena cava was obstructed and the portopulmonary shunt placed by splenopneumopexy was remarkably dilated. There were no other major collaterals of the portal venous system. These findings showed that the hepatic encephalopathy was caused by the change in the portopulmonary shunt. Because hepatic encephalopathy can appear after splenopneumopexy, long-term follow-up may be necessary in patients with Budd-Chiari syndrome who are treated by splenopneumopexy.