A tumor thrombus of the portal vein is refractory to therapy and constitutes a serious prognostic factor in hepatocellular carcinoma. For the purpose of treating portal vein tumor thrombus by restoring the blood flow and preventing recurrent ingrowth of tumor, we devised a metallic stent partially covered with a Dacron mesh sheet, and a coaxial percutaneous delivery system. One half of the wall of a Gianturco Z-stent was covered with a sheet of 0.25-mm-thick Dacron mesh, fixed to the stent wall with nylon threads. The covered stent was implanted in a patient with severe main portal vein stenosis due to tumor thrombus protruding from the left portal vein branch. Immediately after stent placement the tumor stenosis was effectively dilated, the portal blood flow restored, and the portal hypertension relieved. CT and angiography after 8 months still showed complete portal vein patency. Intrahepatic tumor dissemination or other complications were not observed. Intraportal placement of a covered metallic stent appears to be an efficacious therapy of major portal tumor thrombi.