In this work, unloaded WO3 and 0.25-1.0 wt% Pt-loaded WO 3 powders were produced by flame spray pyrolysis (FSP) and structurally characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM). The BET surface area (SSABET) of the nanoparticles was measured by nitrogen adsorption. Thick WO3 films (30 μm) on alumina substrates interdigitated with gold electrodes were prepared by spin-coating technique and tested for gas sensing towards H2, CO, C2H4 and C2H5OH gases at concentrations ranging from 0.01 to 1 vol% in dry air with operating temperatures ranging from 150 to 300 °C. The sensing films exhibited excellent H2 sensing performances with a very high response, short response time and high selectivity towards CO, C 2H4 and C2H5OH gases. The response (within seconds) and recovery (within minutes) times were very fast. It was found that 1.0 wt% Pt-loaded WO3 sensing films showed extremely excellent H2 sensing performances at 150 °C with the highest sensor response (S ∼ 1.34 × 105) and the highest selectivity compared to the other gases. © 2011 Elsevier B.V. All rights reserved.