This study was conducted at the International Center for Textile Research and Development, Texas Tech University, Lubbock, Texas on four Egyptian cotton varieties (Giza 45, Giza 70, Giza 77 ELS and Giza 75 LS variety) and two U.S. cotton ELS varieties (Pima S-7 and Pima S-6) to conduct a comparative study of their fiber and yarn quality. The results showed that Egyptian ELS varieties are longer, stronger and finer than the Pima ones. Therefore, the yarn quality of the Egyptian ELS varieties were higher than those for Pima varieties which were higher than the LS variety Giza 75. Also the Egyptian ELS varieties could be spun to finer counts than Pima ones. Micronaire value proved to be the most contributor to yarn strength and uniformity. Particularly in very fine yarn counts.