Unloaded and 0.25-1.0 wt% Pt-loaded WO3 nanoparticles were synthesized by hydrothermal method using sodium tungstate dihydrate and sodium chloride as precursors in an acidic condition and impregnated using platinum acetylacetonate. Pt-loaded WO3 films on an Al2O3 substrate with interdigitated Au electrodes were prepared by spin-coating technique. The response of WO3 sensors with different Pt-loading concentrations was tested towards 0.01-1.0 vol% of H-2 in air as a function of operating temperature (200-350 degrees C). The 1.0 wt% Pt-loaded WO3 sensing film showed the highest response of similar to 2.16 x 10(4) to 1.0 vol% H-2 at 250 degrees C. Therefore, an operating temperature of 250 degrees C was optimal for H-2 detection. The responses of 1.0 wt% Pt-loaded WO3 sensing film to other flammable gases, including C2H3OH, C2H4 and CO, were considerably less, demonstrating Pt-loaded WO3 sensing film to be highly selective to H-2. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.