Wool fiber was modified using ecologically acceptable ozone-assisted treatment (ECO) in this study. Chemical and mechanical analysis of the treated samples compared with the untreated and Basolan○,R88 treated ones are reported. An atom force microscope (AFM) results show that the crimple was generated on the surface of ECO treated wool fiber and the peak-to-valley decreased slightly. However, Fourier transforms infrared spectra (FTIR) results suggest the absorbency and the oxidation of disulfide bonds increased after the ECO treatment, especially at 1024cm-1. The crystallinity of the treated wool fiber slightly increased based on the X-ray results. The treatment also led to reduction in strength of the wool fiber.