Summary. --The OH(1 x 1)-Ag(ll0) phase obtained after H20 dissociation on the 0(2• 1)-A~(ll0) surface is investigated. Structural and electronic properties are studied by He diffractive scattering and angularly resolved ultraviolet photoemission spectroscopy (ARUPS). Diffractive data are interpreted in terms of the hard corrugated wall (HCW) potential leading to the determination of the corrugation function ~(R). The shape of ~(R) indicates that the phase under study is formed of OH rows along (110) where hydroxil groups interact strongly. The interaction between rows instead is weak and essentially repulsive.