**Abstract**

Chitosan is an important natural cationic polymer. Chitosan is produced as a deacetylated form of chitin, and its excellent biocompatible, biodegradable, nontoxic, natural chemical, and thermal stability properties have led to its common use in especially biomedical applications. The combination of nanomaterials and chitosan has been considered an excellent approach to overcoming the handicaps associated with biopolymer. The chitosan-based nanocomposites are potentially efficient in a number of areas including medical fields. Chitosan is biodegradable, biocompatible, basic, nontoxic, and also approved by GRAS (Generally recognized as safe by the United States Food and Drug Administration [US FDA]). Chitosan-based nanocomposites have different applications in drug delivery including ocular, per-oral, pulmonary, nasal mucosal, gene, buccal drug, vaccine, vaginal, and cancer therapy. Chitosan has low toxicity in both in vitro and in vivo models. *In this* chapter, we discussed the preparation techniques and various forms of chitosan materials in biomedical applications. In addition, this chapter explores recent research on chitosan-based nanocomposites for medical studies.

**Keywords:** chitosan, chitosan-based nanocomposites, clay, biomedical applications
