In patients with cirrhosis, routine laboratory tests for primary hemostasis and coagulation usually show anomalies that are associated with excess bleeding in other settings, in particular low platelet counts and prolonged prothrombin time. However, under conditions similar to those in vivo, primary hemostasis and thrombin production do not appear to be decreased in patients with cirrhosis, particularly when the platelet count is above 75 000/μl. Furthermore, there is laboratory and epidemiological evidence of a mild procoagulant and prothrombotic state in patients with cirrhosis. Bleeding is mainly because of portal hypertension rather than defective hemostasis. There is some evidence that anticoagulation therapy is not associated with an excess of severe bleeding and that it could improve the outcome in patients without portal vein thrombosis. At present, there is no clear evidence that portal vein thrombosis is responsible for the progression of liver disease and that anticoagulation therapy would improve the outcome of patients with portal vein thrombosis.