Lymphocyte subpopulations (total T lymphocytes, active T lymphocytes, late T lymphocytes, B lymphocytes), leukocyte migration inhibition test, serum HBsAg, serum immunoglobulins (IgG, IgA, IgM) were determined in 15 chronic active hepatitis patients and 35 chronic persistent hepatitis patients (diagnosed clinically, biochemically and histologically) and 10 healthy subjects who had acute B viral hepatitis three years ago. A decreased number of total T lymphocytes has been found in HBsAg-seropositive chronic hepatitis. An increase of relative and absolute number of active T lymphocytes was noticed in HBsAg-seronegative healthy persons with a past history of acute viral hepatitis B.