Composite electrolytes for Intermediate Temperature Solid Oxide Fuel Cell (ITSOFC) based on BaO-CeO(2)-GdO(1.5) ternary system have been synthesized through conventional solid state reaction route. X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM) studies confirm a two-phase microstructure. The bulk conductivity in air is found to increase with BaO content, in the temperature range of 150-250 degrees C, while the total conductivity in air at 800 degrees C decreases with BaO content. At 800 degrees C, the Open Cell Voltage (OCV) of Solid Oxide Fuel Cells (SOFCs) constructed using these electrolytes is higher than those for Ce(0.8)Gd(0.2)O(1.9). (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.