This study was carried out to examine the possibility of spinning commercially grown Egyptian Long-Staple cottons on open-end rotor spinning machine into yarn counts finer than the ones regularly spun on these machines using Upland cottons, which could help in increasing demand on Long staple Egyptian cottons, besides helping cotton breeder in Cotton Research Institute in breeding new varieties more appropriate to open-end rotor spin­ning. The five long staple Egyptian cottons; Giza 83, Giza 90, Giza 85. Gin 89 and Giza 86 were spun into 20s. 25s, 30s, 35s and 40s yarn counts at 3.8. 4.0 and 4.2 twist multipliers. Yarn quality pa­rameters were determined. All the Egyptian cotton varieties under study exhibited the same trends in yarn properties as Spinning parameters such as yarn count and twist multiplier were varied, understandably because they are of comparable fibers properties. All the tested Egyptian cotton varieties produced high yarn quality up to the maximum count of 40s. Depending on the yarn quality, particularly yarn strength, elongation % and unevenness, it could be recommended that the Egyptian Long-Staple cotton varieties could be used for the production of rotor yarns up to count 40s. With increasing twist multiplier, yarn strength improved and spinning became more stable. Finer yarns required higher twist multiplier.