The present study wns conducted to develop cre4t4e approaches to determine the quality ol Egyptian cotton varieties by virtue of criteria incorporating combinations of the fundamental fiber quakty characteris­tics of strength, length and intrinsic fineness . Fiber quality index ( FOI ) and staple ratio ( SR) were used. in this connection, as tools for ranking Egyptian cotton varieties included within either the extra-long staple (ELS) category or the long staple (LS) category . Further, FOI and SR were utilized to predict yam strength which is a major quality considera­tion The material used in this study comprised the extra-long staple (ELS) varieties Giza 45. Gin 70, Giza 76. Giza 77. Gin 87. and Giza 88, besides the long Maple ( LS ) varieties Giza 80. Giza 83, Gin 85. Giza 86 and Giza 89 . The study covered the 3 successive seasons of 1996. 1997 and 1998. The findings of this study clarified that the extra-long staple (ELS) varieties have markedly much higher values of either FOI Or SR than the long staple (LS) varieties due to the fact that the ELS cottons have inherently longer, stronger and finer fibers than those of the LS typos. Nevertheless, within each fiber length category, significant differ-eras in either FOI or SR were detected. Further both FOI and SR were found to have significantly positive relation to yam strength indicating that the cottons of higher values of Fat and SR would produce yams of higher strength . However, regression equations were established to pre­dict yarn strength in conformity with FOI and SR values. Ranking of Egyptian cotton vanoties by virtue 01 FOI and SR val­ues indicated that, as concerns the extra-long staple category (ELS). Giza 87 variety ranked first where it significanthz excelled the other va­rieties ol that category, and it was followed in a descending order by Giza 45, Giza 88, Giza 76. Giza 70. and Gin 77. However. Of beton in quality between Giza 88 and Giza 76 was insignificant and the same pat­tern was true as for the quality difference between Giza 70 and Gin 77 varieties. As regards the long staple category (LS). Giza 86 variety proved to have the best quality.followed in a descending order by Gin 89. Giza 85 and Gin 83 . Those last 3 varieties did not differ significant­ly as concerns their quality criteria 01 FOI and SR On the other hand. Giza 80 variety which ranked last in the long staple category. was found to have obviously inferior quality relative to the other varieties com­prised under that category.