The paper presents data on adherence capacity, phagocytic ability, potential cidal capacity of PMN cells in NBT reduction test, activity of myeloperoxidase in the cells, amount and activity of lysozyme in serum, total level of immunoglobulins, including IgG in serum in rabbits immunized with Chlamydia trachomatis, the bacteria which continues to pose a significant threat to humans. Levels of hemoglobin, erythrocytes and leukocytes, blood smears and presence of specific anti-Ch. trachomatis antibodies were also tested. Analysis of the immune variables indicates that immunization with the bacteria has induced alterations in just 7 out of 14 examined immune variables and that in most cases the alterations have involved decreased values and in only few cases elevated values of the parameters. Out of the 8 examined hematological parameters, alterations were noted in only three variables, with augmented and lowered levels noted with a similar frequency. The alterations, particularly those in immunological parameters, were noted 3 weeks before the appearance of specific anti-Ch. trachomatis antibodies.