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Special surfaces based on titanium dioxide are developed for prevention of nosocomial infections. The reactive oxygen species (ROS) have been generated by the surfaces after their UV-irradiation. ROS caused destruction of bacteria. However, effectiveness of bactericidal activity of ТiO 2-films depends on several factors. Influence of time of UV irradiation, thermal (annealing) and chemical (benzene) treatment of films on the bactericidal activity, as well as the bactericidal effect against suspended and lyophilized bacteria have been studied. Three clinical isolates Staphylococcus aureus 956, Staphylococcus epidermidis 1061, Escherichia coli 321-5 have been used. Viability of the suspended bacteria has been determined with use of the classical method of counting CFU, viability of lyophilized bacteria has been determined with use of the method of estimation of coefficients of bactericidal extinction of control and test samples. It has been shown that the bactericidal effect of thin films against all strains increased with an increase in the flow of UV exposure. dermal and chemical treatment caused bactericidal activity recovery which was lost during the initial incubation of the bacterial suspension on the surface. Absence of fluid in the system increased the bactericidal activity of TiO 2-films.