An extensive program of centrifuge tests was undertaken to study the effect of slopes on P-Y curves in dry sand. The paper concerns the method developed in a previous series of centrifuge tests to experimentally determine P-Y curves. Bending-moment curves are fitted by local quintic spline functions through a crossed validation method and then differentiated twice. These experimental P-Y curves are validated by back analysis. The program of tests on piles near slopes is given. It includes studies of the effect of distance to the slope, slope angle, and soil properties. Sample preparation method, model piles, and the lateral-loading device are described. Deflection versus load curves, bending-moment curves, and derived P-Y curves for piles close to slopes are compared to horizontal-ground response. The coefficients that can apply to the P-Y reaction curves of the reference piles (a single pile in horizontal ground) are proposed for use in practice.Key words: pile, slope effets, models, centrifuge, bending moment, P-Y reaction curves.