VEIN GRAFTS have been studied extensively in the systemic venous system. In general, grafts placed in the inferior vena cava have usually failed due to thrombosis, whereas grafts placed in the vena caval system above the diaphragm have met with more success.2,5,6,9,10 The difference in success has been related to variations in blood flow and pressure. In contrast, very little is known of the fate of various grafted materials in the portal venous system. In the present study the influence of portal venous pressure, which is slightly higher than systemic venous pressure, on the maintenance of graft patency was a basic consideration. It was also believed that successful portal vein grafting might have useful clinical implications especially in the treatment of portal hypertension. A five and one-half-year experience with the study of portal vein grafting prompts this report. Earlier reports related some of the immediate and short-term follow-up results.