Wool fabrics were treated with chitosan having various molecular weights and degrees of deacetylation(DD) by pad-dry method. The wool fabric, treated with chitosan having DD>70%, showed an excellent antimicrobial activity irrespective of the molecular weight of the chitosan. Deodorant activity of chitosan-treated wool fabric was increased as the DD of the chitosan increased. Optimum molecular weight of the chitosan to show an excellent deodorant activity was in the range of 100, 000~400, 000. Additionally, the wool fabric treated with chitosan showed a relatively high durability to laundering probably resulted from the strong ionic bonding between chitosan and wool keratin.