Silver and gold have been used for centuries as antimicrobial agents. The aim of the study was to investigate diametral tensile strength, microhardness, ion release and light transmission of experimental resin composites. Flowable dental composite SDR (Dentsply, United Kingdom) was modified by nanogold, nanosilver and silica addition. The metal ion release, light transmission study, microhardness, Diametral Tensile Strength were evaluated. The experimental nanosilver-containing composites released significant amounts of Al, Si, Sr and Ba ions up to 30 days, and negligible silver ion amounts. Significant Ag ion release occurred in nanosilver- and nanogoldmodified composite. Resin composites modified with nanogold and nanosilver deposited on silica carrier exhibit lower light transmission and have opaque appearance. All experimental composites exhibited higher microhardness in comparison to non-modified resin composites. Diametral Tensile Strength of the experimental composites was comparable to the control group.