Segmentectomy is anatomical resection of segments based on the classification of Couinaud. This procedure is performed mainly for hepatocellular carcinoma. Invasion of portal vein and intrahepatic metastases often occur with hepatocellular carcinoma. Thus, it is desirable to perform anatomical resection of the cancer-bearing areas for curative purpose. However, segmentectomy is selected when extensive resection must be avoided to preserve liver function. There are major differences between segmentectomy of the left hemiliver (Sg 2-4) and right hemiliver (Sg 5-8). In the former, the branches (third-order branches) arising from the umbilical portion of the portal vein can be ligated prior to liver resection. In the latter, manipulation is difficult. Therefore, ultrasonically guided segmental staining is performed by puncturing the portal branch and injecting a dye. This report described techniques for segmentectomy.