Metallic nanoparticles with electrochemical and catalytic properties have potential applications for fuel cell/solar cell and sensor electrodes, therefore tremendous efforts have been focused on methods of creating uniformly size distribution at a small range. The silica matrix created by sol-gel method was found to facilitate the formation of metallic nanoparticles with a small size distribution. By using bis-[3-(tnimethoxysilyl)-pnopyl]ethylenediammne, a silica precursor, it was shown that the formation of silver nanoparticles is spontaneous without the needs of reducing agents. Furthermore, metallic nanoparticles are stabilized by the silica precursor during the formation of matrix, making it an ideal method for bioencapsulation. This unique nanocomposite and its synthesis are reported here with evidences from UV-VIS, X-ray diffraction, TEM, and cyclic voltammetry.