The opening roller system for fiber separation in an open end spinning process is known to cause considerable fiber breakage. We have investigated fiber breakage at different opening roller speeds and the relationship between breakage and the properties of friction spun yarns made from cotton, polyester, viscose, and acrylic fibers. A high level of fiber damage caused by the opening rollers occurs at high speeds. The level of damage differs from one sort of material to another. There is a great deterioration in properties when yarns are processed at high opening roller speeds.