In this study, yarns were produced from cotton fibers (CO), recycled cotton fibers obtained from yarn wastes (r-CO) and fibers produced from recycled PET bottles (r-PET). Tensile strength, elongation at break, unevenness (CVm), yarn imperfections (IPI) values and hairiness properties of these yarns were measured. The purpose of this study was to eliminate negative characteristics of recycled cotton and polyester fibers with using together by open-end spinning system. There was no study about r-CO/r-PET blends in the literature. This study was also given significant findings related to these blends. This paper obtained results which corroborate the findings of a considerable number of the previous works in CO/r-CO and CO/r-PET binary blends. Furthermore, this study contributes to the extant literature.