Non-Operative intrahepatic shunts between the left branch of the portal vein and hepatic vein were produced in 14 dogs with periportal cirrhosis and portal hypertension. Dilatation of the intrahepatic fistula was achieved with a Gruentzig catheter with a balloon diameter of 12 m. The catheter was introduced into the left branch of the portal vein passing through the right jugular vein, vena cava and hepatic vein by means of a co-axial system, using a stiff Teflon catheter with an external diameter of 6 mm. Repeated maximal inflation of the balloon, which was placed across the portal vein and inferior vena cava, produced an intra-hepatic portocaval shunt in all dogs. This resulted in immediate abolition of previously stable portal hypertension. The only significant complication was shunt occlusion within a week. In such cases the shunt was reopened by the same technique. The procedure had to be repeated at weekly intervals up to five times before a permanent intrahepatic shunt was established.