This investigation was carried out during 2020 season on the laboratory at Cotton Technology Research Division, Cotton Research Institute, Agricultural Research Center, Giza, Egypt, to investigate the effect of two Egyptian cotton varieties (Giza 80 and Giza 94), and two promising cotton hybrids, i.e. hybrid cotton No. 1 [(G83xG80)xG89]Austrian and hybrid cotton No. 2 [(G89xK)xG86]xG94 on fiber and yarn technological properties under using the new technique of the ring spinning system at yarn count of 40's with 4.0 twist multiplier. The obvious results of this investigation can be summarized as follows: The differences between the studied Egyptian cotton genotypes in all fiber and yarn technological properties were significant, except micronaire value and fiber maturity were not significantly affected by cotton varieties under study during 2020 season. The promising hybrid 2 significantly recorded the highest upper half mean length (mm), fiber mean length (mm), fiber uniformity index (%), fiber bundle strength (g/tex) and lea count strength product vice versa, it gave lowest short fiber index (%), yarn evenness and No. of neps/100 m. Giza 94 cotton variety recorded maximum fiber stiffness (g/tex) and fiber brightness degree (Rd %), however it gave lowest fiber elongation percentage and fiber yellowness degree (+b). Maximum short fiber index (%), fiber yellowness degree (+b), yarn evenness and No. of neps/100 m as well as, the minimum upper half mean length (mm), fiber mean length (mm), fiber uniformity index (%), fiber bundle strength (g/tex), fiber stiffness (g/tex), fiber toughness (g/tex), fiber brightness degree (%) and lea count strength product which obtained from Giza 80 cotton variety. The fiber which obtained from promising hybrid 1 recorded greatest fiber elongation percentage and fiber toughness (g/tex).