The non-linear inverse model described in Mercier et al. (1992) is used to estimate the mean surface topography of the North Atlantic and its formal error. The surface is based on a large hydrographic and Lagrangian data set and has spatial resolution of 2-degrees in latitude by 2.5-degrees in longitude. The formal error is between 4 and 8 cm. Contrary to previous estimations, this takes into account the errors with regard both to the density field and to the estimation of the velocity field at a reference level.