The influence of a chitosan application on wool fabric before a treatment with a proteolytic enzyme has been investigated. The enzymatic treatment enhances whiteness and confers shrink resistance to wool, but an increase in the enzyme concentration leads to a detrimental effect on the physicomechanical properties. A chitosan treatment before the enzymatic treatment additionally improves the shrink resistance and increases the weight loss. To better investigate the role played by the chitosan, surface-related properties, such as the friction coefficient, the compressional behavior (compressibility, linearity of compression, and thickness), the wearing resistance (weight loss after abrasion), the bursting resistance (bursting strength and deformation), and surface topography, have been studied. The results suggest that the chitosan pretreatment reduces the damage caused by the subsequent enzymatic treatment. They also imply a protective effect of the bursting and wearing resistance, which prevent excessive weight loss due to abrasion. A significant influence of the wool fiber cell membrane complex on the surface-related properties has been demonstrated through regression analysis and scanning electron microscopy observations. (c) 2005 Wiley Periodicals, Inc.