We report on electric properties of Ag-x(As(0.33)Ch(0.67))(100 - x) (Ch S, Se, Te) glass systems in relation to their microstructure and changing constituting chalcogenide atoms. We observed decreasing contribution of the ionic conductivity when sulphur was replaced by selenium and tellurium. We also found a strong correlation between the conductivity and the phase separation into a silver-rich and a silver-poor phase which appears to be responsible for the semiconductor - ionic conductor transition in the sulphur and selenium based systems. (C) 2010 Elsevier By. All rights reserved.