Inelastic electron tunneling spectroscopy was used to study the adsorption of acetylene on palladium particles supported by alumina. Low peak intensities in the spectra complicated the analysis of the multiple species present. Nevertheless, some species could be tentatively identified including weakly bonded acetylene, two types of strongly bonded acetylenic species and two other further rehybridized species. The prospect for the future application of tunneling spectroscopy to the study of other hydrocarbons adsorbed on model supported metal catalysts is discussed. (Author).