Abstract—The biological activity of chitosan asparaginate particles formed in the chitosan‒L-aspartic acid‒water system at the initial stage of phase separation was investigated. Cultivation of Staphylococcus aureus 209 P and Escherichia coli 113-13 in the medium supplemented with nanoparticles resulted in massive death of bacterial cultures. The biocidal activity against gram-positive bacteria was most pronounced. Biological tests revealed high biocompatibility of chitosan nanoparticles and their ability to accelerate the proliferative activity of the cultures of epidermal and epithelial cells. Our results indicate that chitosan asparaginate nanoparticles are promising for medico-biological and pharmaceutical applications.