The article focuses on a polysaccharide of natural origin – chitosan and its application in tissue engineering. The preparation process and physicochemical properties of the saccharide are described. The degradation of chitosan and the properties influencing the process both outside and in living organism were examined. Four applications in bone tissue engineering can be distinguished: preparation of cell scaffolds exclusively from chitosan, from a chitosan composite or from a chitosan polyelectrolyte complex. The fourth way is to modify the surface of scaffolds made of other materials by covering them with a layer of chitosan. At the end of the article, the processes taking place after placing the implant inside the body are described, how the structure of chitosan affects the behaviour of bone cells in the adhesion process and life processes.