ABSTRACT. – In recent years, massive water blooms of cyanobacteria occurred in many freshwater lakes and reservoirs, and cause severe water quality problems including scum formation, toxin production, taste and odors, and hypoxia generation. Therefore, a new environmental friendly method was proposed for cyanobacterial bloom mitigation using chitosan and illite. The effects of particle size of illite, addition of illite, addition of chitosan on Microcystis aeruginosa removal was examined through batch experiments. The results showed that the removal efficiency of cyanobacteria had a strong dependence on the changes of particle size of illite, addition of illite, addition of chitosan. The highest removal efficiency, 97.42 %, was obtained under the optimal conditions. This study demonstrated that there were technically viable methods using chitosan and illite to remove M. aeruginosa cells