Electrodynamic properties of L285 polymers, filled with graphite nanoplatelets (GNP) and TiO(2)have been investigated in frequency ranges 1 kHz-2 MHz and 26 GHz-60 GHz. The TiO(2)particles are expected to improve the dispersion of GNPs and have been shown to increase complex permittivity, with values of the real part reaching 22 in 40-60 GHz range. The values are generally higher than permittivity of composites, filled with pure GNP or mix of GNP and BaTiO3, however the dielectric losses increase sharply on reaching 4% GNP content. These properties could be used in microwave absorbers, where having higher dielectric loss is important, as well as real part of permittivity.