The paper addresses the optimization of various machine parameters in rotor spinning system to obtain the highest quality index of cotton yarn produced from the ginning process waste. The effect of rotor parameters a diameter and speed, navel type, opener speed, separator type and yarn linear density on the yarn quality were investigated, using the Taguchi method. Also, the optimum spinning conditions for the rotor yarns produced from different ginning waste proportions (65%, 50% and 35%) were determined.