The present study was conducted to establish a new standard yarn count for the open-end rotor spinning for routine testing of Long-Staple cottons. Also, twist multiplier; count correction and determination of the number of lea breaks were studied. Five Egyptian Long-Staple cotton varieties namely Giza 80, Giza 83, Giza 90, Giza 85 and Giza 89 were used in this trial.According to the degree of precision, the nominal count 30s with 4.4 twist multiplier was chosen as an appropriate yam count based on lea strength variation and optimum quality. Furthermore, ring yarn count level in the Egyptian spinning mills is around 28.5s. The three regression coefficient values of -1.3, -1.5 and —1.9 appeared to be not suitable to be used for correcting the observed lea strength with 30s yarn count since they increased the coefficient of variation in the corrected lea product of tested cottons. The acceptable number of leas for a test was recorded as 24 leas.