Organophilic Bentonities clays are widely used for industrial purposes, as components of petroleum drilling fluids as well as in cosmetics, lubricants adhesives and paints. Most recent they have been used as fillers in polymer nanocomposites. In this work, three organophilic bentonitic clays from the distric of Boa Vista and one from Campina Grande, PB, Brazil, were synthesized and characterized. The four clays were treated with a quaternary chloride ammonium salt- dimethyl benzyl ammonium alkyl chloride (Dodigen 1611) provided by Chemco. The cation exchange and swelling capacities of the modified clays were determined and the clays were characterized by FTIR, Thermal Analysis (DTA, TGA) and X-ray diffraction. The results showed the modification of all four clays by the quaternary ammonium salt to be successful.