A wet-chemistry method was used to dope F- ions into crystalline TiO2 by hydrothermal treatment of TiF4in an HCl solution. Field-emission electron microscope and transmission electron microscope images showedthat the products exhibited a flowerlike morphology with a hollow interior. X-ray photoelectron spectroscopedata demonstrated the doping of F in the lattice of crystalline TiO2. The flowerlike F-doped TiO2 hollowmicrospheres synthesized at 180 °C showed the highest photocatalytic activity for the degradation of methyleneblue under visible light irradiation. Ostwald ripening is the main reason responsible for the formation of thehollow interior of the F-doped TiO2 micropheres, and the HF species generated from the hydrothermal reactionis believed to accelerate the formation of the TiO2 hollow spheres.