Thick film H-2 sensors were fabricated using SnO2 loaded with Ag2O and PtOx. The nano-crystalline powders of SnO2-Ag2O-PtOx composites synthesized by a sol-gel method were screen printed on alumina substrates. The fabricated sensors were tested against gases like H-2, CH4, C3H8, C2H5OH and SO2. The composition that gave the highest response to H-2 was SnO2:Ag2O:PtOx = 93:5:2 in wt% ratio. The composite material was found to be sensitive to H-2, with minor interference of other gases, at a working temperature of 125 degrees C. H-2 gas as low as 100ppm could be detected by the present fabricated sensor. It was found that the sensor based on the SnO2-Ag2O-PtOx nano-crystalline system exhibited high-performance, high selectivity and very short response time to H-2 at ppm level. These characteristics make the sensor to be a promising candidate for detecting low concentrations of H-2. (c) 2007 Published by Elsevier B.V.