Mesoporous titania–silica oxide materials of various compositions with high crystallinity and predominantly in the anatase modification were produced by hydrolysis and subsequent heat treatment of a mixture of titanium tetrachloride and oligodimethylsiloxane (ODMS) containing terminal Si–Cl groups. The synthesized samples were tested as photocatalysts in the destruction of methylene blue dye in aqueous solutions. The highest activity, significantly exceeding the activity of commercial TiO2, the highest specific surface area, and porosity was exhibited by the photocatalyst prepared from 33 wt.% ODMS. The photocatalysts are active not only under the action of UV but also of visible light. This may be due to the effect of carbon doping of TiO2 during ODMS decomposition, which increases the light absorption and improves the separation of the photogenerated charges.