We have performed molecular dynamics simulations at 150 and 200K to study the structure of ice adlayers on MgO(100). An improved interaction potential based on a distribution of electric multipole moments and polarizabilities on the water molecules was used which accounted for the non-local nature of H 2 O and for the self-consistent polarization of water in the presence of the substrate electric field. The monolayer geometry and the structure of the first steps of multilayering are determined, and are shown to be in good agreement with previous calculations which used the simplest potentials and electron diffraction, and with helium scattering and infrared spectroscopy experiments. The present calculations corroborate the existence of a stable, nearly planar water monolayer. The centers of mass of the H 2 O molecules adopt a square arrangement commensurate with the substrate network, leading to weak hydrogen bonds between adjacent molecules. Although the layers above the monolayer appear less ordered, they display at these temperatures a geometry which looks like a distorted hexagonal ice-like ordering with strong hydrogen bonding.