A commercial tubular titania membrane was coated by alumina oxide using sol-gel technique. The membrane was used to separate pure gases of H-2, N-2, CO and CO2. The permeabilities of H-2 from a binary mixture of H-2/N-2, H-2/CO and H-2/CO2 were measured using the membrane at high-temperature region (1073 K). An experimental rig was designed and fabricated to perform the permeability studies of H-2 from the binary gas mixture. Effect of feed rate, feed concentration and average pressure on permeability of pure gas and a binary mixture of H-2 were studied. Results showed that the H-2 separation factor for binary mixture of H-2/CO2 is the highest followed by H-2/CO and H-2/N-2 for all feed concentration. The permeability of gases across the coated alumina-titania composite membrane increased slightly with increase of average pressure. Experimental data were compared with the theoretical values using complete mixing model and the separation factor was calculated experimentally and theoretically. The results showed a good agreement between experimental data and the theoretical predictions. The permeability of gases across the coated alumina-titania composite membrane increased slightly with increase of average pressure. (C) 2003 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.