Conjugates of target cells and of cytological T-lymphocytes obtained on the 11th day after alloimmunization were investigated. The conjugates formed small and medium lymphocytes; mature secretory granules, crystal-like structures and lipids were revealed in their cytoplasm. The lymphocyte is spherical, the area of contact with the target cell does not exceed 5 to 15%. Cytolysis of target cells is observed after 30 to 60 minutes of incubation. The lymphocyte becomes flattened, its nucleus acquires an oval form, and the area of contact with the target cell increases considerably. At the same time hypertrophy and change of orientation of Golgi's complex to the area of contact with the target cell, coalescence of the secretory granules with lipids and crystal-like structures, the appearance of immature secretory granules and vacuolar degeneration of mitochondria are demonstrated. The lymphocyte membrane becomes "desquamated"; structures connected with it, named "membranosomes" are described. It is suggested that the secretory processes in the cytoplasm of cytolytic T-lymphocytes are activated in their interaction with target cells.