This experiment was carried out to examine the MBC adsorption on clay minerals by the slurry method. The adsorption of MBC on Kaolinite nearly reached equilibrium after shaking for 2hrs. but on Bentonite and Zeolite, l0hrs., respectively. The adsorption amount was in the order of Zeotite$gt;Bentonite$gt;Kaolinite, and Na-saturated clay mineral adsorbed more MBC than Mg-saturated clay mineral did. The more the amount of clay minerals, the more MBC was adsorbed by clay minerals, whereas the amount of MBC adsorbed per unit gram of clay minerals reduced and Kd value cf MBC was greatest on the Na-Zeolite. The lower the pH of the water-clay system at each concentration, the more MBC was adsorbed by clay minerals. The pH dependence of the adsorption of MBC may be due to protonation of MBC in acid solution.