Polyelectrolyte complex nanoparticles of chitosan and carboxymethyl cashew gum (CMCG) were prepared with CMCG with two different degrees of substitution (DS = 0.16 and 0.36). The effects of polymer concentration, molar mixing ratio (n (+)/n (-)) and mixing order of reactants on particle size distribution and zeta potential were investigated. Nanoparticle structure was elucidated by Fourier transform spectroscopy. Particle size of CH/CMCG DS = 0.16 dispersions was smaller than with DS 0.36 for all n (+)/n (-) ratio investigated. Particle size smaller than 200 nm was obtained when CMCG with DS = 0.16 was used for particle formation. The polydispersity index values were small when CMCG DS 0.36 was used. Increasing the concentration of CMCG led to larger particle size. Zeta potential values for almost all molar mixing ratios were found to be positive (10-32 mV).