The determination of the content of thermostable T-lymphocytes in the peripheral blood in 184 patients with acute virus hepatitis, as well as at the stage of the termination of the disease, has revealed the increased number of cells belonging to this subpopulation in all the groups under study. At the acute stage of the disease a rise in the number of thermostable T-cells is directly related to the severity of the process. Of different variants of the termination of hepatitis B, the highest content of thermostable T-cells is observed in chronic active hepatitis and chronic HBsAg carriership, while in chronic persistent hepatitis the content of thermostable T-cells is considerably lower.