XPS and UPS methods have been used to study the nature of the oxygen states on silver. Three oxygen states with high E-b(O1s) = 530.5 eV(O-epox), 530.9 eV(O-beta), 532.0eV(O-res) can be reliably attributed to different adsorbed species of quasimolecular oxygen. These states are characterized by an unusually high thermostability(T > 800 K) and a subsurface location.