This study provided a facile method to prepare nano-TiO2/polystyrene hybride microspheres in ethanol solution. The formation of titanium dioxide (TiO2) nanoparticles and hybrid microspheres were verified by FTIR, SEM, transmission electron microscopy, thermogravimetric analysis, and X-ray powder diffraction. Monodispersed colloid TiO2 nanoparticles with small particle sizes were obtained, and the average particle size could be effectively controlled from about 10 nm. The antibacterial activity of the organic microspheres and hybride microspheres was also investigated against Escherichia coli. They were able to efficiently inhibit the growth and the multiplication of E. coli under the UV. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 116: 779-784, 2010