Differential resistance analysis (DRA) is used for determination of authentic bulk conductivity of yttrium-doped barium cerate proton conductors (BCY) using electrochemical impedance spectroscopy (EIS), by eliminating all electrode and fixture resistance as well as interfacial or surface phenomena. Bulk conductivity determined using DRA in the range 500-800 degrees C was higher by a factor of 1.5-3 than values obtained for conductivity of the same electrolyte using EIS alone. Application of DRA with EIS provides geometrically independent conductivity values. (C) 2008 Elsevier B.V. All rights reserved.