Little attention has been paid to a ligation of the spontaneous portosystemic shunt in adult living donor liver transplantation (LDLT). A 33-year-old Japanese man with cryptogenic liver cirrhosis accompanied by a huge splenorenal shunt underwent LDLT. Acute cellular rejection produced "to and fro" portal venous flow on postoperative day (POD) 10. Steroid bolus therapy reversed the rejection, but the recovery of the portal venous flow was incomplete and the recipient subsequently started to have episodes of encephalopathy. Angiography showed portal hypoperfusion and portal flow steal via a huge splenorenal shunt. The patient underwent a shunt occlusion on POD 58. Portography showed marked improvement of the portal hypoperfusion. The encephalopathy thereafter dramatically reversed and the patient was discharged with no complications related to shunt ligation on POD 110. This case suggested that a ligation of a huge portosystemic shunt should therefore be considered at the time of transplantation, even when a relatively small graft is implanted.