Nanometric TiO2 and nickel-doped TiO2 powders were obtained by thermal decomposition of non-alkoxide precursors prepared using an ultrasonic-assisted sol–gel method. Ti4+ and Ni2+ were obtained from titanium oxide sulfate hydrate and nickel sulfate hexahydrate, respectively. X-ray powder diffraction and Raman spectroscopy confirmed the formation of only the anatase phase in both oxides, and no titanates were observed. The Ni-doped material was determined to be a solid solution with a stoichiometry of Ti0.96Ni0.04O2−y. The incorporation of nickel lowers the band gap calculated from the UV–Vis diffuse reflectance spectroscopic data, and affects the specific surface area, density, and acid–base characteristics. Mesoporosity developed as a result of particle agglomeration and differed among samples, as determined based on the total pore volume.