Twelve commercial Egyptian cotton cultivars were used in this study. Samples of the studied cultivars were taken from the miniature experiments conducted by CRI, ARC, Giza during the two successive seasons i.e.1992 and 1993 from ten growth regions in Egypt.

“Standard Method” for estimating fiber maturity was performed as degree of thickening percent by swelling fibers with NaOH 18% on different group lengths of samples which sorted by the Suter-Webb device. Among the three methods used to estimate fiber maturity, viz., DTP, LORD 1961 and Shirley F/MT instrument. The F/MT seemed to be preferable by the cotton breeder to be used in routine work, since its measurements were close to the standard method “DTP” and it is rapid and accurate as compared to the “DTP” and LORD methods, which are tedious and time consuming. Ribbon width as well as micronaire reading were discussed in this study.