Cellulose and chitin are the most abundant polysaccharides in nature. Chitin is the natural amino polysaccharide and is estimated to be produced annually almost as much as cellulose. These resources are renewable and inexhaustible if rationally utilised. Unique properties of chitin and chitosan (chitin derivative obtained by the deacetylation of chitin), such as antibacterial activity, biocompatibility, non-toxicity and bioresorptivity make these materials very suitable and important biomaterials. During our studies, we examined the possibilities of obtaining composite, biologically active cellulose-chitosan fibres. Аn effective two-stage procedure for obtaining antibacterial fibers based on cellulose and chitosan was developed. The first stage involves the formation of dialdehyde cellulose by potassium periodate oxidation of cellulose fibers, which is able to form Schiff's base with chitosan. In the second stage, chitosan coated cellulose fibers were prepared by subsequent treatment of oxidized cellulose fibers with a solution of chitosan in aqueous acetic acid. Maximum percentage of chitosan introduced into/onto the cellulose fibers was 0,51 % (w/w). Antibacterial activity of cellulose fibers coated with chitosan as the active component against bacteria Escherichia coli and Staphylococcus aureus, was confirmed by in vitro experiments.