A 56-year-old male patient with chronic C type hepatitis had HCC which invaded right portal vein trunk (Vp3). In August 2000, we performed intrahepatic artery infusion chemotherapy with CDDP and 5-FU under subcutaneous interferon alpha treatment. In addition, we used chemoradiation therapy for portal tumor thrombus in HCC. As the result of such therapy, the size of HCC and portal tumor thrombus reduced and the level of PIVKA-II decreased. There were no side effects except fever due to interferon alpha treatment. In February 2001, we performed devascularization and RFA therapy for HCC in S7 of liver under laparoscope. The level of PIVKA-II was within the normal range. It is important to perform interdisciplinary therapy appropriate for the HCC status.