In this study, denim fabrics were produced with yarns obtained from cotton fibers (CO), recycled cotton fibers obtained from yarn wastes (r-CO), and fibers produced from recycled PET bottles (r-PET). Enzyme and stone washing processes were applied systematically on these fabrics. Mass per unit area, breaking force, elongation at max force, tear strength, air permeability, and circular bending rigidity of fabrics were measured. The findings showed that r-CO fiber has negative effect on tear and breaking force. Breaking force, elongation at max force, and tear strength values of the fabrics increased depending on the increase in r-PET content. However, fabric handle was negatively affected associated with the r-PET ratio due to the increase in stiffness. Mass per unit area, breaking force, air permeability, and circular bending rigidity values of fabrics decreased after the washing processes. The effect of fibers on enzyme-or stone-washed fabrics showed a change according to finished fabrics. It can be said that fabrics containing r-PET are more resistant than cotton and recycled cotton in various aggressive denim washing methods such as bleaching or different washing process conditions such as rising temperature, and time.