Electrical and dielectrical properties of Cu6PS5I1-xClx superionic composites, obtained by mixing of microcrystalline powder with polyvinylacetate, are studied. Compositional dependences of their electrical conductivity and dielectric permittivity, measured in the frequency range of 10 Hz-3 GHz at 300-400 K, are analyzed. The effect of compositional disordering on electrical and dielectrical properties at I -> Cl anionic substitution in the Cu6PS5I1 - xClx superionic composites is investigated. (C) 2012 Elsevier B.V. All rights reserved.