Portal vein thrombosis (PVT) has a heterogeneous aetiology. Recently discovered thrombotic risk factors such as latent myeloproliferative disorders and prothrombotic genetic defects are important in the aetiology of PVT. At least one-third of the PVT patients exhibit a combination of thrombotic risk factors. Treatment with anticoagulant drugs has not proved beneficial for most PVT patients. Therapy with anticoagulants is only recommended in those with acute PVT, in those who recently underwent a portosystemic shunt procedure and in those with other thrombotic manifestations, particularly in case of proved hypercoagulability. Due to intact coagulation, oesophageal varices bleeding in patients with PVT has a better prognosis than in cirrhotics.