Chitosan is a natural polymer obtained by deacetylation of chitin, with excellent biocompatible properties thanks to -NH2 and -OH functional groups. It has a polycationic nature, which enables interactions with various biomolecules such as DNA, proteins and lipids. Depending on the degree of deacetylation and the method of preparation, there are different properties and degrees of purity. The favorable properties make chitosan useful in a number of industrial applications, including applications in medicine, pharmacy, agronomy, cosmetics, tissue engineering and the food industry. Important biological properties of chitosan are biodegradability, biocompatibility, antimicrobial, hemostatic, fungistatic and anti-inflammatory action and the ability of mucoadhesion, which can promote wound healing, restoration of cartilage and bone tissue. Chitosan is a polysaccharide soluble in diluted acid solutions, which enables the preparation of materials of different shapes depending on their purpose, such as films, fibers, microparticles or porous structures. The aim of this work is the preparation, identification and characterization of films based on chitosan modified with boric acid in order to improve the biological properties of chitosan. The films were prepared by the casting and drying method, while identification and characterization was carried out with the help of Fourier transform infrared spectroscopic analysis (FTIR), X-ray diffraction analysis (XRD) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS). The influence of different degrees of deacetylation of chitosan (85 and 95 %) and types of solvents (acetone, sodium hydroxide) during preparation on the composition of the films was investigated.