Chitin separated from natural resources has three polymorphic crystalline structures: α, β, and γ. The physicochemical properties of chitin are differently presented according to these structures. The properties of α-chitin and β-chitin have been observed by many investigators, but those of γ-chitin, first proposed by Rudall et al., have not been revealed until now because of the unusual nature of the raw material. In this study, γ-chitin has been separated and characterized. Also, the properties of α-chitin and β-chitin have been compared with those of γ-chitin.