Carboxymethyl chitin and carboxymethyl chitosan have low oxygen permeability, so they can be used as antiseptics. Moreover, water solubility of carboxymethyl chitin and carboxymethyl chitosan make them possible to be applied in groceries and medicines. In this study, biomedical grade chitin and chitosan were extracted from chionoecetes opilio and carboxymethyl chitin anal carboxymethyl chitosan which can be applied in groceries and medicines were obtained from them. The reaction conditions of carboxymethylation such as NaOH concentration. reaction temperature and reaction time were investigated by means of monitoring of viscosity. In addition, some properties were compared with biomedical grade carboxymethyl chitin and carboxymethyl chitosan commercialized by NOVA chemical.