A promising cotton inbred line characterized by high yielding ability, earliness in maturity and better fiber quality was developed via pedigree selection from the subsequent segregating generations of a cross between the two long-staple cvs.; Giza 89 and Giza 86 by the Cotton Breeding Section of the Cotton Research Institute. The purpose of this investigation aimed at assessment of the superiority of the physical and fine structural properties of the promising line derived from the cross (Giza 89 x Giza 86) over its parents. The results indicated that: -  The promising line surpassed its parents in upper half mean length, uniformity index, fiber strength, fiber elongation, micronaire value, maturity ratio, hair weight, dry fiber ribbon width, swollen fiber diameter, convolution number / cm., reversals number/ cm. and yarn strength. - There were highly significant positive correlations between upper half mean length, uniformity index, convolution number/cm., fiber bundle strength and yarn strength. - Highly significant negative correlations exhisted between dry fiber ribbon width, swollen fiber diameter, reversals number and bundle strength.   The promising line is now under propagation for growing as a commercial cultivar and would replace both parents in their growing areas.