TiO2 nanoparticles were successfully synthesized by a wet impregnation method using SBA-15 or AP-SBA-15 as the template for confining the growth of TiO2 nanocrystals followed by acclimation at 550 ¢J in muffle furnace for 6 hrs. These uniform nano-sized TiO2 particles are difficult to prepare using the conventional sol-gel process since the decomposition of the Ti precursor proceeds rapidly to form large aggregates, resulting in a wide particle size distribution. The as-synthesized samples were characterized with powder X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectra (FTIR), and nitrogen adsorption isotherm. Results from TEM reveal that the TiO2 nanoparticles are highly dispersed in the channels of SBA-15; subsequent removal of the SBA-15 channels with HF gives the pure TiO2 nanoparticles having a diameter of ~ 9 nm. On the other hand, the bulk TiO2 outside the SBA-15 channels mainly forms aggregated large TiO2 particles. Prior treatment of SBA-15 surface with the coupling agent APTS (AP-SBA-15) enhances the easy chemosorption of a great number of titanium. Subsequent hydrolysis of the anchored Ti complexes and calcinations of the amorphous TiO2, anatase TiO2 nanocrystals yields uniform TiO2 nanoparticles having diameter of ~ 5 nm, as compared to the unconfined bulk TiO2 of 15~50 nm in diameter.