An 11-month-old female infant underwent living-donor liver transplantation for secondary biliary cirrhosis 8 months after Kasai operation. The portal vein was hypoplastic, and its diameter was only 4 mm at the level of the splenomesenteric confluence. End-to-end anastomosis of the recipient suprarenal vena cava to the graft portal vein (a left lateral section from the patient's mother) was performed. An end-to-side portocaval shunt with the recipient portal vein was constructed to mitigate portal hypertension. The early postoperative course was relatively uneventful. However, persistent hepatitis caused by infection with Cytomegalovirus and chronic rejection resulted in progressive hepatic dysfunction. Nine months after the initial operation, a living-donor retransplantation (a left lateral section from the patient's grandmother) was performed. One month after retransplantation, severe acute rejection that eventually required OKT3 treatment developed. The patient was in excellent health until 4 months after retransplantation, when another acute rejection episode (for which she was successfully treated) developed. Cavoportal hemitransposition should be included in the armamentarium of the transplant surgeon for the management of extensive portal system thrombosis and portal vein hypoplasia. An additional shunt may be useful in mitigating portal hypertension.