Biodegradable polymers are increasingly being researched for the purpose of substitution of synthetic polymers because their use reduces CO2 emissions and environmental pollution. Chitosan, as one of the biodegradable polymers, finds its application in the food and pharmaceutical industry, and in the production and development of coatings with new, functional properties. In this work, chitosan (Cs) films and chitosan nanocomposites with zinc oxide (Cs-ZnO) were studied in order to investigate the functional property of antimicrobial activity. Chitosan films were prepared by dissolving high molecular weight chitosan (100.000 -300.000 Da) in 1 % acetic acid solution, and nanocomposite films were also prepared by dissolving chitosan in acetic acid with the addition of zinc oxide (ZnO) nanoparticles (5 mass.%). Characterization of chitosan film samples was performed by determining the contact angle with a goniometer, mechanical properties; tensile strength and tensile elongation were determined by the stress-strain method. By scanning electron microscope (SEM) morphology has been characterized, in order to determine the dispersion of nanoparticles in chitosan. Also, the antimicrobial activity of chitosan films (Cs and Cs-ZnO) was examined on three type bacterial cultures: Escherichia coli (3001), Pseudomonas aeruginosa (3011) and Bacillus subtilis (3020). The results showed that nanocomposite film (Cs-ZnO) has improved properties compared to pure chitosan film (Cs). The mechanical properties of nanocomposite film (Cs-ZnO) are increased because the tensile strength and tensile elongation have higher values, also the same samples showed higher antimicrobial activity.