The valence state of Bi on Pt(lll) which is irreversibly deposited at underpotentials from perchloric acid solutions, has been determined ex-situ by XPS for various emersion potentials. From chemical shift measurements it is inferred that the adsorbed Bi remains in its zero-valent state over the entire potential range under study, despite a substantial charge flow during cycling. This charge is attributed to OH-adsorption on the Pi-covered Pt(lll) surface rather than to a change in Valence state of the adsorbed Bi. as was previously suggested. Superstructures were observed in the LEED patterns and are assigned to ordered Bi adlayers.