WO3/Nb2O5-supported samples prepared by impregnation are characterised by X-ray diffraction (XRD), Raman spectroscopy and X-ray absorption spectroscopy (XAS) at the W-L-3 absorption edge, as well as temperature programmed reduction (TPR) and FT-IR monitoring of pyridine adsorption. Results are compared with those obtained for WO3/Al2O3 samples prepared in the same conditions, showing that niobia is able to disperse tungsta better than alumina does. Formation of a crystalline WO3 needs larger tungsten contents on niobia than on alumina, since tungsten solution into niobia is easier than into alumina. Raman and XAS spectra recorded under ambient conditions suggest that similar WO, species are formed on both supports at tungsten contents 0.5-1 theoretical monolayers; however, TPR results for the low tungsten loaded samples indicate that, when reduction starts (always at temperatures higher than 700 K under H-2/Ar flow) there is a larger concentration of tetrahedral [WO4] species on alumina, than on niobia. Samples with low tungsten loading have been tested in isopropanol decomposition and ethylene oxidation, following both processes by FT-IR of adsorbed species up to 673 K. Results show that adsorption of ethylene on WO3/Nb2O5 yields acetaldehyde and acetate at 473 K, while this adsorption is non-reactive either on the supports or on WO3/Al2O3. Isopropanol adsorbs dissociatively on both supports, leading to acetone and propene formation on tungsta-niobia, but only propene on tungsta-alumina, probably due to the larger reducibility of the tungsten-containing phases.