A case of hepatocellular carcinoma (HCC) with tumor thrombi in the vein in the major omentum is reported. A 54-year-old man underwent a second operation for recurrent HCC. Intraoperative ultrasonography revealed a tumor thrombus in the vein of the adhering omentum. Part of the antero-inferior area of the liver adjacent to the tumor was resected with the major omentum. Since it is characteristic of HCC often to form tumor thrombi in the veins, it is not surprising that the tumor budded into the epiploic vein. This is apparently the first report of tumor thrombi of HCC in the epiploic vein.