Objective: The aim of this study was to clarify the impact of combined preoperative three dimensional computed tomography (3D-CT) imaging and intraoperative real-time 3D-ultrasonography (US) imaging on image navigation for hepatic resection. Patients and Methods: An integrated navigation system using combined preoperative 3D-CT images and intraoperative real-time 3D-US images were used with patients who underwent hepatic resection for liver tumors, including HCC, cholangiocarcinoma and metastatic liver cancer, and for donor hepatectomy for living related liver transplantation. 3D-CT imaging was made using the workstation "ZIO M900" (ZIO software, Inc., Tokyo, Japan). 3D-US was made in real-time during an operation using the ultrasonographic device SSD5500 (ALOKA, Tokyo, Japan) and the workstation "SAS 200"(ATOKA, Tokyo, Japan). Results: The 3D-CT imaging from CT during hepatic arteriography gave us details of the arteries feeding the tumor. By 3D-CT imaging from CT during arterial portography, the recognition of Glisson's branches in the liver, as well as the hepatic venous system, was much easier than conventional 2D-CT imaging. 3D-US images allowed us to understand the anatomy of the liver more easily than from 2D-US images, and the 3D-US images could reinforce in real-time preoperative information using 3D-CT images. Conclusions: Combined preoperative 3D-CT and intraoperative realtime 3D-US provides us with integrated information of liver anatomy, especially the spatial relationship between tumor and intrahepatic vessels, which can not be visualized because of their location inside of the liver. Intraoperative 3D-US imaging can reinforce preoperative excellent 3D-CT imaging. Therefore, our integrated navigation system consisting of combined 3D-CT and 3D-US is useful for liver surgery.