The residuary waters of tanneries are loaded by many heavy metals notably of the chromium. This last one is often used in excess to improve the quality of tanning, and by this fact, the waters of dismissal are concentrated strongly in ion chromium-plates. Several works showed the different properties developed by the clay such as; their capacities of exchanges cationique and their properties of surface. These properties confer to the clay important adsorption properties. In this work, we have studied the adsorption of chromium ions by the natural and modified clays in order to reduce the pollution of used waters. The several techniques are used, in this study: DRX, infra red, isotherms adsorption of nitrogen (specific surface and porosity) and atomic absorption for chemical analysis. The results show that the clay used either natural or modified, by pillaring, present an important affinity for the Chromium ions.