This study was conducted to assess the removal effi ciency of pesticide (organophosphorés) used, on a c lay originated from barrage situated in a west of Alger ia. The adsorption of pesticides from aqueous solut ion by local clay as a low-cost, natural and eco-friendly adsorb ent was investigated. Different physicochemical par ameters were analyzed: adsorbent mass, initial concentration of pollutant, and pH. The empirical results showed tha t all these parameters have an impact on the retention of pesti cide on the clay. The equilibrium uptake was increa sed with an increase in the initial pesticide concentration in solution. The results of adsorption were fitted to the Langmuir and Freundlich isotherms. The Freundlich model represen ted the adsorption process better than Langmuir mod el, the exploitation of these isotherms follows the Freundl ich model shows that the coefficient n obtained is within the range expected by Hassler 0.2-0.8, which is found t hat the mud is a good adsorbent for our pesticide