The influence of chitin nanofibrils on the production of chitosan-based fibers is described in the article. The chitosan-based fibers and composite fibers were prepared from an aqueous solution of 2-% acetic acid using the coagulation method. The incorporation of 0.1-0.3 % of mass fractions of CNs into the chitosan matrix contributed to an increase in the mechanical properties of the composite fibers. The chitosan nanofibers were spun with electrospinning from a 70-% acetic-acid aqueous solution of chitosan containing 10 % of mass fractions of PEO and 1-30 % of mass fractions of CNs. The introduction of CNs into chitosan solutions accelerates considerably the quality of nanofibers at the electric field and decreases the amounts of defects in them. The optimal concentration of CNs for producing defect-free chitosan nanofibers was 20 % of mass fractions.