Chitosan is one of promising polymers for applications in various fields. However, despite diverse research studies conducted on its biocompatibility, its uses are still limited. The main factor that can affect its physical, chemical and biological properties is the degree of deacetylation (DOD), which represents the proportion of deacetylated units in the polymer. In this article, the in vivo biocompatibility of chitosan-hydroxyapatite composite films composed of chitosan with different DOD values was. The chitosan with the higher DOD induced a higher incidence of inflammation. This basic study on the relationship between the DOD and inflammation is valuable for the development of further chitosan-based researches.