The topic of this paper is the synthesis of chitosan nanoparticles, the theme selection is related to the interestingness of chitosan applicability in many fields of science. The purpose of the thesis is to optimize the method of obtaining chitosan nanoparticles in laboratory conditions. Numerous methods of preparation of nanoparticles exists, for chitosan nanoparticles preparation methods are: ionotropic gelation, microemulsion method, emulsification solvent diffusion method, polyelectrolyte complexes, reverse micellar method. In this thesis we have used the ionotropic gelation method, this method is based on the linkage by electrostatic atrractive forces between the chitosans protonated amino group and the polyanion. Polymers are compounds of high molecular weight which are made of the basic building blocks of monomers that are interconnected. Polymers can be natural, semi-synthetic and synthetic, examples of natural polymers are proteins, ellulose, starch, nucleic acid, and between polysynthetic and chitosan derived from the chitin. Chitin can be found in some plants, but in large quantities it is found in the exoskeleton of arthropods and shellfish shells. Chitosan is a polymers consisting of two monomers of N-acetyl-2-amino-2-deoxy-D-glucopyranose and 2- amino-2-deoxy-D-glucopyranose which are mutually linked to the β- (1 → 4) glycosidic linkage. Chitosan for commercial needs is most often obtained by the deacetylation process of chitin, which is further used for various purposes from pharmacy, medicine, agriculture to environmental protection. The deacetylation process is most commonly carried out with a base such as sodium or potassium hydroxide at a certain temperature. Fine chitosan particles required for different applications in medicine or pharmacy often have dimensions less than 500 nm. The nanoparticles are useful because they have special properties, which can be different from the large particles made of same material, because of their small dimensions, the active surface increases. The reason for the change of both the chemical and physical properties is that ratio of the surface and the volume of particles, or the ratio of the number of atoms located on the surface of the particle and within the particle. In some cases, most of the atoms can be found on the surface of the particles rather than in the interior. By means of the results obtained in this work,we can synthesize chitosan nanoparticles of a desired size by precise modeling, ie precise concentration and chitosan molecular mass selection, and chitosan to TPP (tripolyphosphate) ratios.