A series of Ag 0 nanoparticle materials supported in SiO 2 were synthesized by the sol-gel method, with contents of 2, 5 and 10% w/w. The fresh samples were calcinated and reduced with H 2 at 500 °C in order to obtain Ag 0 . The materials obtained were studied by X-ray diffraction, N 2 physisorption, UV-vis spectroscopy, electronic transmission microscopy and EDS (energy dispersive spectrometer). The antibacterial activity was observed in the deactivation of E. coli in its liquid phase, using the plate count method to identify viable CFU (colony forming units). The results show that the materials containing Ag nanoparticles dispersed in SiO 2 increase their bactericidal efficiency on the increase of the content and size of Ag nanoparticles.