Linoleic acid (LA) capsulated in chitosancapsule was dispersed in phosphate buffer, and oxidized by 2, 2'-Azobis-(2-amidinopropane)-dihydrochloride (AAPH). The oxidative stability of capsulated LA was extremely higher than that of aqueous micelles. These results suggest that chitosan-capsule would be useful items tp protect fatty acids against oxidants.