Living-donor liver transplant for a big hepatocellular carcinoma located in the caudate lobe is challenging owing to dissemination of cancer cells during recipient hepatectomy. We report a case of living-donor liver transplant using the right side of the liver of a living donor combined with inferior vena cava interposition graft after en bloc resection of the liver and retrohepatic inferior vena cava for hepatocellular carcinoma in the caudate lobe. A 50-year-old man with chronic hepatitis B cirrhosis developed hepatocellular carcinoma in the caudate lobe and segment 5. The diameters of the masses were 4.5 cm and 2.5 cm. His model for end-stage liver disease score was 17, and he had a moderate amount of ascites. For the recipient hepatectomy, en bloc resection of the entire liver, including retrohepatic inferior vena cava and reconstruction of inferior vena cava with Dacron graft, were performed. We then performed a transplant of the right lobe taken from the living donor. This technique can be a new alternative curative treatment option for hepatocellular carcinoma located on the hepatocaval confluence or close to the inferior vena cava. We should evaluate the long-term safety for cancer recurrence and infection of an artificial vascular graft in the milieu of immunosuppression after liver transplant.