Ozone adsorption at 77 K on titania (anatase) surface dehydrated at different temperatures or preexposed to pyridine, acetonitrile, and CO has been studied by infrared spectroscopy in order to characterize ozone interaction with Lewis acid sites of different strength. With weaker sites, ozone molecules form coordinative complexes bound via the terminal oxygen atom. The observed vibrational frequencies (about 1145 and 990 cm(-1)), as well as the isotopic shifts observed for ozone enriched by O-18, reveal a strong distortion of the molecule in this complex. No molecular adsorption of ozone on strong Lewis sites was detected. Data obtained provide evidence for ozone dissociation on these sites. Formation of atomic oxygen is suggested. It participates in oxidation of CO on the TiO2 surface.