The formation of a tin layer on a palladium surface and the dissolution of the adsorbed layer have been investigated. Different oxidation states of the adsorbed tin deposit and irreversible adsorption were observed. Site requirement of an adsorbed tin atom was found to be about 2. In addition to the potentiostatic deposition, adsorption via the ionization of preadsorbed hydrogen and disproportionation of Sn2+ ions were also examined.