This study was conducted at Sakha Agricultural Research Station, Cotton Research Institute, Agricultural Research Center, Kafr El-Sheikh Governorate, Egypt, during two growing seasons (2021 and 2022). Six Egyptian cotton varieties were used as lines with five genotypes as testers, using line x tester analysis. Genotypes, parents, crosses and parents vs. crosses mean squares were extremely significant for all the studied characters, except for micronaire reading in the crosses. Giza 94 x 10229 exhibited significant useful heterosis (BP) for all the studied characters. Lines Giza 86 and Giza 76 recorded significantly and positive desirable general combining ability effects (GCA) for most traits while, Giza 96 was significant desirable general combining ability effects for fiber quality characters. In this respect, testers showed that Uzbekistan had significant and positive desirable for most yield characters while, BBB had significant desirable general combining ability effects for most studied characters. Crosses Giza 96 x Australy13, Giza 86 x 10229 and Giza 75 x C.B.58 were significant desirable specific combining ability effects (SCA) for some yield traits. Generally, Giza 86 could be used for improving high yielding cotton varieties in plant breeding programs, while Giza 96 considered as beneficial parent for breeding programs to produce new varieties characterized with best fiber quality.