As compared to other hepatitis-inducing viruses, hepatitis B (HBV) and hepatitis C (HCV) viruses pose the globally most serious hazard to public health, evoking acute and chronic hepatitis, liver cirrhosis, hepatocellular cancer and extra-hepatic syndromes. The most significant trait of the two viruses involves their capacity to induce chronic infections, linked to an inadequate immune reaction of the infected host. Results of investigations indicate an important role of lymphocyte Th cytokine response in the course of chronic HBV or HCV infection. Therefore, in present paper current data have been summed up on secretory activity of lymphocytes Th in chronic hepatitis B and chronic hepatitis C. Also, the data have been presented on novel immunotherapeutic strategies in the above mentioned morbid syndromes.