Nanotechnology plays a key role in many different fields, including electronics, energy, and biology. Drug delivery systems rely heavily on nanoparticles, such as nanotubes, dendrimers, and lipid-based carriers, since they enable targeted distribution with the least number of adverse effects. Polymers or polymer science is primarily responsible for the unique physicochemical properties of nanoparticles. The second most common polysaccharide, chitin, and its derivative, chitosan, are highlighted in this chapter because they are becoming more and more viable materials for the formulation of nanoparticles. Because of its many uses and well-known biodegradability, chitosan sticks out in drug delivery systems by shielding bioactive substances. This chapter emphasizes the various preparation methods of chitin and chitin-based nanoparticles, majorly the ionic gelation technique, coacervation method, spray drying, and emulsification solvent evaporation method. Further, various characterization methods for the elucidation of chitin-based nanoparticles have been discussed, such as spectroscopy techniques like UV–visible and FTIR, dynamic light scattering technique, microscopy, and zeta potential. These characterization methods provide important insights into the physicochemical characteristics necessary to understand chitin-based nanoparticles’ behaviour and possible uses.