Immunomodulatory activity of doxorubicine was assessed with the use of two screening tests: test of cytotoxicity and test of hemagglutination. Substance of proved immunosuppressive properties, that is cyclosporine A was used for comparison. The obtained results show that doxorubicine increases survival rate of mouse thymocytes in cultures with hydrocortisone. Agglutination titre of mouse serum (active hemagglutination test) following doxorubicine injection evidenced a distinct reduction in immunoglobulins representing IgM+IgG and IgG classes in comparison to the control group, which received buffered saline solution. Doxorubicine at the applied concentrations stimulates cell response while inhibiting humoral response of the mouse immunological system.