PURPOSE: To determine the prevalence of variations in the intrahepatic portions of portal veins, as visualized by arterial portograms, and to examine the surgical implications of these findings in Koreans. MATERIALS AND METHODS: Five hundred and nineteen arterial portograms of 519 patients with no evidence of vascular tumor invasion or distortion were retrospectively reviewed. In all patients, the main, right, right anterior, right posterior and left portal vein were visualized. RESULTS: Variations in intrahepatic portal anatomy were found in 102 patients (19.6%) and involved an immediate trifurcation of the main portal vein in 82 (15.8%) a right posterior segment from the main portal vein in ten (1.9%), a right anterior segment from the left portal vein in nine (1.7%) and an absent horizontal portion from the left portal vein in one (0.2%). CONCLUSION: On arterial portogram, variations in the intrahepatic portions of the portal veins are frequently seen. The recognition of such variations is important in the preoperative evaluation of patients with hepatic tumors, since the variations may have implications for tumor resection, for the localization of tumor thrombi and in interventional radiologic procedures involving the portal vein.