This paper reports the synthesis, structure, chemical stability and electrical transport properties of Ti substituted Ba3CaNb2O9 (BCN) to develop electrolytes for proton conducting solid oxide fuel cells (H-SOFCs). The powder X-ray diffraction (PXRD) of Ba3CaNb2-xTixO9-delta (x =0.1, 0.15. 0.2, 0.25 and 0.3) and Ba3Ca1.18Nb1.82-xTixO9-delta (x=0.15 and 0.25) showed formation of double perovskite-like structure with lattice constant comparable to that of Ba3Ca1.18Nb1.82O9-delta (BCN18). Scanning electron microscopy (SEM) showed dense and pore-free microstructure for Ba3CaNb1.75Ti0.25O8.875. PXRD and Fourier transform infrared (FTIR) spectroscopy data confirmed long-term stability of Ba3CaNb2-xTixO9-delta and Ba3Ca1.18Nb1.82-xTixO9-delta in boiling H2O and in CO2 at elevated temperatures. The AC impedance investigation showed contribution due to bulk, grain-boundary and electrode effect at low temperatures. The electrical conductivity of studied materials were measured in different medium including dry air, dry H-2, wet H-2, wet N-2 and D2O. Increase in conductivity in wet N-2 and decrease in conductivity in D2O confirmed the proton conduction in Ba3CaNb1.75Ti0.25O9-delta. Among Ti-substituted compounds investigated in this study, Ba3Ca1.18Nb1.57Ti0.25O8.605 showed the highest conductivity of 3.5 x 10(-4) S cm(-1) at 400 degrees C in wet N-2 (3%H2O), which is comparable to reported values of Ba2Ca0.79Nb0.66Ta0.55O6-delta and BCN18. (C) 2010 Elsevier Ltd. All rights reserved.