Chronic hepatitis B is one of the world's most common infectious diseases. In the Czech Republic it has a prevalence of 0.56%. Antiviral therapy for chronic hepatitis B demonstrably increases quality of life and where indication criteria are met and standard therapeutic procedures are followed, it is clearly cheaper than treatment for the complications of advanced cirrhosis of the liver or hepatocellular carcinoma. At the time of issuing of this recommendation, 4 medicines were classified for the treatment of chronic hepatitis B in the Czech Republic--pegylated interferon (IFN) alpha-2a, conventional IFN alpha, lamivudine (LAM) and adefovir dipivoxil (ADV). In a number of other developed states, entecavir (ETV) and telbivudine (LdT) have also been approved for treatment. The most effective treatment available at present is pegylated IFN alpha-2a, which should be the medication of first choice for initial treatment of hepatitis B, HBeAg positive and negative forms, provided that there are no contraindications for IFN alpha treatment. Conventional (standard, classical) IFN alpha can also be used, though clinical studies have shown it to be less effective than pegylated IFN alpha-2a. The main advantage of interferon compared to other commercially available medications is its relatively shorter and more clearly defined treatment period, the high probability of permanent suppression of virus replication and seroconversion of HBeAg/anti-HBe (in HBeAg positive forms of the illness) and the non-creation of mutant strains of HBV resistant to IFN in the course of treatment. If there are contraindications for IFN alpha (pegylated or conventional) or it is ineffective or poorly tolerated, ADV, ETV, LAM or LdT can be used. LAM and LdT treatments are often accompanied by the appearance of mutant strains of HBV, that are resistant to lamivudine or LdT and therefore they are not preferred.