Immunisation of mice with SolcoUrovac vaccine induced an approximately 10-fold increase of the total amount of IgG and a 2-fold increase of IgA immunoglobulins in urine. IgG antibodies to SolcoUrovac antigens appeared in urine after the first injection, and booster injections caused a further increase of the titer. IgA antibodies appeared in the urine after the second injection, and the third injection doubled the titer. IgM immunoglobulins and specific IgM class antibodies to SolcoUrovac were not found in any urine tested. The exact origin of the immunoglobulins in the urine as well as the specificity of immune response is discussed.