The fibrous wastes appear during processing of cotton fabrics in spinning, weaving, knitting and clothing technologies. These wastes are treated in recycling units. Main aim is tearing up into cotton fibrous bundles and destroying of non fibrous wastes or very short fibrous fragments. Resulting reprocessed cotton fibers are carded for elimination of entangled fibers or yarns debris. Reprocessed cotton fibers can be used for creation of coarse rotor yarns (about 50 tex) by shortened rotor technology (carding, drafting, spinning). For finer yarns can be reprocessed cotton fibers mixed with PES staple fibers. Main goals of this work are comparison of rotor yarn properties created from cotton fibers and reprocessed cotton fibers. The properties of both raw materials were measured by AFIS system combined with measurement of tenacity and elongation to break. For complex characterization of quality the utility value based index was computed. The Uster statistics were used as well. The reprocessed cotton fibers quality index has significantly low value due to lower upper quartile length, length uniformity, short fiber content and neps. Structure of rotor yarns was characterized by analysis of surface and cross section. Yarn quality was evaluated from measurement of unevenness, hairiness and mechanical properties. Results show that reprocessed cotton fibers can be used for creation of yarns with comparative properties with common yarns from cotton fibers. The higher twist coefficient of yarn from reprocessed cotton fibers is necessary. ACKNOWLEDGEMENTS This work was supported by the research project 1M4674788501 of Czech Ministry of Education. REFERENCES [1] Militký, J.: Complex Quality of Cotton fibers. FAO/ESCORENA International Conference Textiles for Sustainable development 23-27 October 2005, Port Elisabeth, South Africa. [2] Kremenakova at all: Internal standards. Research Textile Center 2004. Faculty of Textile Engineering Technical University of  Liberec.