Electric force microscopy (EFM) and conductive atomic force microcopy (C-AFM) are introduced to perform nanoscale electrical characterization of phase separated Ag-x(Ge0.25Se0.75)(100-x) glasses. Changes in the relative permittivity are found for both phases when the silver content is changed. Furthermore, the sensitivity of the C-AFM technique revealed current variations of a few pico-amperes in the Ag-rich phase for the different glass compositions. This result confirms that the increase in conductivity of the Ag-Ge-Se samples in the region of high ionic conduction (x > 8-10 at.%) arises from an increase in conductivity of the Ag-rich phase and not from an increase in amount of Ag-rich phase with a fixed composition and conductivity. (C) 2010 Elsevier B.V. All rights reserved.