Two recipients of orthotopic liver transplants (OLT) underwent intra-arterial thrombolytic treatment for hepatic artery thrombosis. Complete clot lysis was achieved in both using infusion of high-dose urokinase directly into the thrombus for 12 and 3 hours, respectively. Percutaneous transluminal angioplasty (PTA) was later carried out successfully on various strictures. Doppler ultrasonography confirmed arterial permeability one month after treatment. Liver transplantation is now an accepted therapeutic option in some patients with irreversible liver failure. Although the results of this procedure have improved radically since cyclosporine was introduced in 1978, life-threatening postoperative complications still occur. The one with the worst prognosis is hepatic artery thrombosis (HAT), with 64% mortality despite retransplantation. HAT was found in 7.4% of liver transplant recipients in a recent review of the most important group of these patients. Fibrinolytic treatment using an exogenous plasminogen activator, urokinase (UK), is effective and safe in the thrombotic obstruction of acute pulmonary embolism, acute myocardial infarction, and graft or peripheral arterial occlusion. We used intra-arterial thrombolysis in two patients with HAT of the liver graft, to avoid retransplantation and to treat a complication secondary to percutaneous transluminal angioplasty (PTA) of an anastomotic stricture, respectively. To our knowledge, this is the first report of treatment of HAT by direct infusion of urokinase in liver transplantation.