The best indicator of the severity of liver damage and prognosis in chronic viral hepatitis is extension of liver fibrosis. Extension of liver fibrosis can be assessed by liver biopsy and non-invasive physical or biological methods. Biopsy is used to define ethiology, severity (stage of fibrosis) and prognosis of liver disease. These informations are also usefull when estimating the risk-benefit and deciding on the modalities of antiviral therapy. Serological tests and elastography may distinguish significant fibrosis (F > or = 2) from baseline fibrosis (AUROC 0.77-0.83 for serology and 0.84 for elastography) and cirrhosis from noncirrhotic stages (AUROC 0.77-0.86 for serology and 0.9-0.94 for elastography). Individual method of choice with best performance to distinguish cirrhosis from noncirrhotic stages of liver is elastography. Combination of serological tests and transient elastography has 93-95% accuracy to predict liver cirrhosis, and in case of concordant values of both tests biopsy could be avoided in 77-80% of patients. In case of discordant values or those in favour of intermediate stages of fibrosis liver biopsy should be performed because in these situations non-invasive tests are less reliable. According to several studies liver stiffness as assessed by transient elastography has high predictive value for the development of decompensated cirrhosis and portal hypertensive complications and may also discriminate the patients with respect to the predicted 5-year survival.