Portal vein thrombosis is often considered a contraindication to orthotopic liver transplantation. We have analyzed the incidence, risk factors, management and outcome of patients with portal vein thrombosis undergoing orthotopic liver transplantation. During the period from October 1988 to October 1992 140 grafts were performed on 132 patients. Fourteen had portal vein thrombosis with either partial (n = 7) or complete (n = 7) occlusion of the portal vein at surgery. Portal vein thrombosis was more common in patients with autoimmune chronic active hepatitis (3/5 vs. 11/127, chi 2 = 13.3, P < 0.001), cryptogenic cirrhosis (4/12 vs. 10/120, chi 2 = 7.2, P < 0.01), or those with tumors (6/22 vs. 10/110, chi 2 = 5.7, P < 0.05). In 13 of the 14 portal inflow was reestablished by flushing, balloon thrombectomy, or passage of a graduated dilator. In one patient complete fibrous obliteration necessitated a portal vein to right gastroepiploic vein anastomosis. On follow-up there have been 6 deaths in this group (6/14 = 43%) from recurrent cancer (n = 1), sepsis (n = 4), and cardiac and renal failure (n = 1). Four of these 6 patients had confirmation of PV patency on imaging. The remaining 8 patients are alive and well (median follow-up 37 months, range 6-53 months). Post-transplant portal vein thrombosis occurred in 3 of the 14 patients (21%) with a portal vein abnormality at surgery and in two of the 118 patients with a normal portal vein (3/14 vs. 2/118, chi 2 = 8.5, P < 0.01). Four of the 5 cases were successfully treated by surgical thrombectomy.