Chitin is a polysaccharide of N-acetylglucosamine (GlcNAc) residues joined by β(1 → 4) glycosidic links that forms the cell walls of fungi, the exoskeletons of arthropods, and special structures of mollusks, cephalopods, and even some fish species. In endoparasites, this polymer is a component of the nematode eggshell, the protective sheath of microfilariae, and the cyst walls of protozoa, but is also expressed at the cell surface of trichomonad species. Chitin is synthesized by the stepwise polymerization of GlcNAc from UDP-GlcNAc as catalyzed by chitin synthase. The straight chains of the chitin polymer are important for the maintenance of the structural integrity and protection of the organism from environmental, chemical, and mechanical damages. As chitin synthesis and assembly do not occur in higher animals, these processes serve as targets for antiparasite chemotherapy.