Thrombosis of the main hepatic vessels is a severe, frequent complication in patients requiring liver transplantation. It is usually a cause of emergency retransplantation. Two cases of hepatic vascular thrombosis secondary to disseminated aspergillosis are presented. Both patients demonstrated a septic state and required a second transplantation despite which they died within a few days. Necropsy showed disseminated aspergillosis with invasion of the portal venous system and the hepatic artery. The risk factors associated with this infection and the possible pathogenic mechanisms are discussed.