In this study, we develop a bactericidal coating material for micro-implant, TiO2 films with Ag deposited on were prepared on titanium plates by sol-gel process. Their anti-microbial properties were analyzed as a function of the annealed temperature using Escherichia coli as a benchmark microorganism. Ag nanoparticles deposited on TiO2 film were of metallic nature and could grow to larger ones when the annealed temperature increased. The results indicated that the smaller size of Ag nanoparticles, the better bactericidal ability. On the other hand, the positive antibacterial effect of TiO2 enhanced the bactericidal effect of Ag. (C) 2010 Elsevier B.V. All rights reserved.