Considering coal-water slurries (CWS) as dispersed systems with a large separation surface, we have studied the adsorption of same species at the solid-liquid interface; these species have been necessary for the preparation and stabilization of coal-water-slurries (CWS). In this paper, we report the results of the study on the adsorption of poly-naphthalene sulphonates (PNS) and poly-styrene sulphonates (PSS) with controlled molecular weight and steric purity, at model coal/water interfaces and at the real coal/water once