In liver resection, severe bleeding can be prevented by appropriate surgical techniques. These include adequate access and mobilisation, vascular occlusion, controlled dissection of the parenchyma, prevention of venous "over-filling" and secure hemostasis of the resection surface. Excessive bleeding, both in liver resection and liver transplantation, poses a major risk for the development of postoperative complications. In liver transplantation the surgeon is most often confronted with patients with chronic liver disease and portal hypertension. Coagulation disorders are the rule, and the surgery itself is more demanding because of fragile venous collaterals as a consequence of portal hypertension. With the use of extracorporeal venovenous bypass or newer techniques with preservation of the vena cava, some of these difficulties can be overcome. Pharmacological therapies like administration of aprotinin can reduce the fibrinolysis inherent in liver transplantation. However, surgical skill and experience are probably still the most important predictors of blood loss during surgery.