The paper discusses the Y and Nd doped barium cerate perovskites prepared by a modified Pechim method. The series prepared is described by the formula BaCe0.80YNd0.2-x O3-delta. The BaCeO3 based powders, about 10-20 nm sized and uniformly shaped, were obtained through the calcination of the gel at 500 degrees C for 2 h. Their structures and ionic conductivities were characterized by X-ray diffraction and AC impedance spectroscopy. All the electrolytes were found to be barium cerate based solid solutions of perovskite type structures. Impedance spectra indicate that the grain boundary resistance of the specimen synthesized by this method is smaller than that of the samples prepared by a conventional solid-state method. The ionic conductivities of co-doped barium cerate were a factor of several times than that of the single-doped one at 673-1073 K. Among the electrolytes examined, the one co-doped with 5 mol% Nd and 15 mol% Y shows the best improvement in performance. These co-doped barium cerate are more ideal intermediate temperature (IT) electrolyte materials. (c) 2006 Elsevier B.V. All rights reserved.