A comparative study was performed of the multiplicity of anodic current peaks related to the potentiostatic adsorption and the voltammetric and potentiostatic electro-oxidation of adsorbed CO on smooth polycrystalline, electrodispersed, smooth faceted and rough faceted Pt electrodes. The strength of the Pt-CO interactions appears to be strongly influenced by the adsorption potential, whereas the electro-oxidation of the CO adsorbate, which involves an interaction between adsorbed CO and 0-containing surface species resulting from water electroadsorption, is influenced mainly by the Pt surface texture. A complex reaction pathway involving the interconversion for CO adsorbate electro-oxidation is proposed. The interconversion of the CO adsorbate depends on both the time required for the overall reaction and the texture of the Pt electrode surface.