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) ) and two U.S. cotton varieties: (Pima S-7 and Pima S-6) to investigate the spinning potential of the two types of cotton. The SPY test (Spinning Potential Yarn Number) was performed for both carded and combed roving. Results indicated that Egyptian ELS varieties were of higher spinning potential yarn number and yarn quality than the Pima ones. Stepwise regression analysis indicated that micronaire value was the most important fiber property contributing to the spinning potential of both the carded and combed cotton.