Аннотация:We have found that the value of chitosan adsorption is strongly depends on nanodiamonds surface properties: nitration and air oxidation of originally positively charged nanodiamonds results in the significant increase in chitosan adsorption. It has to be emphasized that only air annealing results in the changing in zeta potential of the original material. After chitosan adsorption zeta potential of all types of nanodiamonds converts to positive value close to 35 mV. Thus, chitosan modified nanodiamonds forms suspensions that possess higher stability in the aquatic media. However, the values of particle size of modified nanodiamonds in the aqueous suspension were two times higher than for the original material.