Hepatocellular carcinoma (HCC) is the third most common cause of cancer-related deaths worldwide with about 600,000 patients dying from the disease annually. In 70-90%, HCC develops on the background of chronic liver cirrhosis or inflammation. Risk factors and etiologies vary among geographical regions. In regions with a high incidence the majority of cases are related to HBV and HCV hepatitis. In developed countries, in addition to virus-related HCC, high consumption of alcohol as well as non-alcoholic fatty liver disease often in the context of metabolic syndromes are the prevalent causes. Improvement in clinical management of patients with liver cirrhosis and the control of related complications are the key for the rising incidence of HCC. This review gives an overview on epidemiological trends and risk factors and their mechanisms involved in the hepatocarcinogenesis. Knowledge of these factors will help to improve current concepts for prevention, screening and treatment of this disease.