Thin Pd-Pt and Pd-Rh electrodes (Pd surface content up to 80% by at) were electrochem. deposited on Au support and used for studying adsorption of C oxides and oxidn. of their adsorption products. The adsorbates were characterized by voltammetry. Max surface coverage with adsorbed CO was higher than with adsorbed CO, The coverage was higher on Pd-Pt than on Pd-Rh alloys. The electrode per site values for CO2 were higher than for CO on Rh-rich Pd-Rh alloys, while on Pd-Pt and Rh-poor Pd-Rh alloys an opposite relation was observed. The addn. of Pd did not result in any improvement of the removal of adsorbed C oxides. Adsorbed CO2 cannot be totally identified with adsorbed CO on Pd-Pt and Pd-Rh alloys.