The aim of presented study is the investigation of clay minerals utilization in the wastewater treatment. The chemical treatability studies were carried out by the refined packing type kaolinite (hydrate aluminum silicate). By testing kaolinite as coagulant and flocculant separately within the experimental studies, optimum doses were determined, and on the basis of treatment efficiencies, results were compared with the chemicals such as alum, lime and ferric chloride which are widely used. The removal of organic matter was deter-mined according to Chemical Oxygen Demand (COD) parameter. Higher treatment efficiencies were obtained when kaolinite was used as flocculant. For the domestic wastewater, 82% organic matter, 70% suspended solids matter, and 23% oil-grease removals were achieved when alum was used as coagulant and kaolinite was used as flocculant. The turbidity of wastewater was removed completely, and insignificant differences were observed in pH parameter. For industrial wastewater samples, the highest efficiency was obtained when ferric chloride was used as coagulant and kaolinite was used as flocculant. In this case, 99% organic matter, 83% suspended solids matter, and 85% oil-grease removals were obtained. For the industrial wastewater treatment, the usage of kaolinite as coagulant yielded also efficient results, 96% COD removal was obtained.