The effect of titania (TiO2) addition on the densification, crystal structure and electrical property of Ce0.8Gd0.2O1.9 (GDC) are examined. TiO2 addition reduces GDC sintering temperature by similar to 200 degrees C and considerably improves grain boundary conduction. The minimum grain boundary resistivity is obtained at 0.8 mol% TiO2 concentration. XRD analysis suggests that the solubility limit of TiO2 in GDC is similar to 0.6 mol%. The optimum doping level (0.8 mol%) is slightly higher than the solubility limit (0.6 mol%), which implies that a small amounts of TiO2 (similar to 0.2 mol%) at the grain boundaries benefits the grain-boundary conduction. Copyright (c) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.