Specific features of formation and the composition and characteristics of dispersed phase particles in mixed dilute solutions of chitosan and magnesium sulfate, containing no surfactants, were studied. The component molar ratio, \(\nu _{SO_4 } :\nu _{NH_2 }\), is the factor exerting the strongest influence on the formation rate and characteristics of chitosan sulfate particles. With an increase in the fraction of sulfate ions in the initial solution, the particle size decreases and their ζ-potential increases. The \(\nu _{SO_4 } :\nu _{NH_2 }\) molar ratio in chitosan sulfate particles only slightly depends on the composition of the initial mixed solution and varies within 0.40–0.44.