The nature of the adsorbates formed when benzyl alcohol interacts with palladium in 0.1 M HClO4 was studied via on-line differential electrochemical mass spectroscopy (DEMS), in situ Fourier transform infrared spectroscopy (FTIR), and cyclic voltammetry. Oxidative and reductive stripping experiments, as well as adsorbate displacement by CO, render valuable information concerning the nature of the adsorbed residues. Using isotope-labeled (C6H5CH2OH)-C-12-C-13, it was possible to discriminate the respective behavior of the alcohol group and the aromatic ring. Adsorbate yields were found to strongly depend on the adsorption potential. Toluene, benzene, and CO are the residues formed from benzyl alcohol on palladium in the hydrogen adsorption/absorption range, whereas the intact benzyl alcohol molecule and benzoate seem to be the main species adsorbed on a hydrogen-free electrode.