The liver is an organ with many indispensable functions in the body. Liver diseases can be caused by numerous ethiological factors, and are divided into two basic groups, according to an anatomical substrate which is primarily affected – on hepatocellular (parenchymal) and billiard diseases. Approximately 10% of patients with liver disease require a surgical procedure (not including a liver transplant) in the last 2 years of life. Because of its reserves and regenerative abilities, the liver can suffer a great deal of damage before the clinical manifestations of its own dysfunction, which is a challenge for the pre-operative assessment of its condition. The goal of preoperative screening is to determine the presence of preexisting liver disease without the need for extensive or invasive testing. Routine testing of liver function has a low prediction value. The post-operative outcome depends on the nature and severity of the existing liver disease, as well as the type of the operation. It is often necessary to treat complications of severe liver damage, such as coagulopathy, thrombocytopenia, ascites, kidney failure, encephalopathy and malnutrition. Predisposition for infections of patients with cirrhosis requires prophilactic use of antibiotics. Induction of anesthesia, bleeding during surgery, hypoxia, hypotension, the use of vasoactive drugs, and even positioning of patients and surgical techniques can reduce intraoperative and perioperative delivery of oxygen in liver and increase the risk of hepatic dysfunction. Pharmacokinetic parameters of anesthetic agents, muscle relaxants, painkillers and sedatives may be altered in connection with plasma proteins, detoxification in liver etc.. The postoperative liver dysfunction depends on surgical trauma, ischemia during surgery or loss of hepatocite mass, and it can be divided into three groups – hepatocelulcular, cholesterol and mixed liver dysfunction. Posthepatectomy liver failure is one of the most serious complications after the liver resection and is a post-operative deterioration of liver capability to maintain its main functions. In recent years, liver function support systems have been developed. Molecular recirculation system with absorption (MARS), modified fractional plasma separations and adsorption (Prometheus) and bioartifical liver and extracorporal device for assistence of liver activity. Extensive clinical studies are needed to prove the effectiveness of these artefical systems for temporary replacement of the edible functions to its recovery or to transplantation.