Nanocrystalline fluorinated titania has been prepared using microwave-assisted hydrothermal crystallization of hydrous titania in a NH4F aqueous solution. Thus, obtained TiO2 has exhibited excellent photocatalytic activity in the reaction of crystal violet dye photodegradation – up to twofold higher than the photocatalytic activity of the commercial Evonik Aeroxide® TiO2 P25 photocatalyst. Hydrothermal treatment temperature and the concentration of ammonium fluoride in the reaction mixture have been shown to be key parameters, providing the most significant effect on the microstructure and photocatalytic activity of titania.