Alumina silicate powder which is extracted from the obsolete spark plug NGK (insulator part as a filler) has been used to produce epoxy/alumina silicate composite. The dielectric behavior of the composite materials (epoxy resin-alumina silicate NGK) is analyzed as a function of the filler content, temperature and frequency. AC conductivity and impedance are also studied. The results show that the permittivity, dielectric loss and loss tangent for all composites increase with increasing alumina silicate NGK filler content.