Chitosan, one of the natural biodegradable polymers, has widely been investigated in diverse fields of textile application in addition to the food or medical applications. Three different molecular weight chitosan samples, 8, 46, 830 cp, were used for treating fabrics. Polyester/cotton spun yarn fabric and polyester filament yarn fabric were dipped in the chitosan solution, cured, neutralized in NaOH solution, and finally heat-set. Mechanical and physical properties of the chitosan treated fabric samples were investigated using KES (Kawabata Evaluation System) and other instruments.