A direct shunt between the inferior mesenteric vein and the inferior vena cava was detected in a patient with hepatic encephalopathy. The authors performed balloon-occluded retrograde transvenous obliteration (BRTO) for this shunt. Before the obliteration, the shunt was occluded by using a balloon catheter and it was confirmed that the portal venous flow was redirected to the liver. The encephalopathy disappeared immediately after BRTO. The improvement of the liver function, the disappearance of the shunt, and the increase in the size of the portal vein and liver volume were confirmed at computed tomography performed 5 months after treatment.