The aim of the study was assessment of hepatocyte apoptosis depending on expression of Fas and FasL proteins by various liver cells in patients with chronic viral hepatitis B (CVHB) or chronic viral hepatitis C (CVHC). The symptoms of hepatocyte apoptosis were observed in 3 of 12 patients with CVHB and in 9 of 14 patients with CVHC, the proportion of apoptotic cells being 12-65%. Hepatocytes of healthy people and patients with hepatitis B or C express Fas protein in the cytoplasm diffusely, as granules or on cell membrane. In health, hepatocytes do not express FasL, but in CVH they do. The highest apoptosis was observed in Fas protein location as granules in cytoplasm or in their preferable location on the cell membrane. The severity of hepatocyte apoptosis in CVH directly correlated with FasL expression by the cells of the lymphoid-histiocytic infiltrate in the liver and inversely correlated with FasL expression by hepatocytes. Thus, a great part of hepatocytes in CVH are killed by the virus; Fas/FasL interaction is leading in damage to hepatocytes in CVH.