A three-phase epoxy-based composite with randomly distributed silver nanoparticles and BaTiO3 particles was synthesized. By the incorporation of silver nanoparticles into the epoxy resin, the dielectric properties of the resin were significantly enhanced, and this provided an ideal host for further mixing with BaTiO3 to prepare high dielectric-constant, polymer-based dielectrics with high dielectric strength. The devices that adopted these composites demonstrated high relative dielectric constants of approximately 450, 110 times higher than that of the epoxy matrix, with a dielectric strength of 5 kV/mm at room temperature. These nanocomposites were found to be potentially useful for embedded capacitor applications. (c) 2006 Wiley Periodicals, Inc.