This study aims to study of some different off-types and the effect of the characteristics of these plants on genetic purity. Ten off types were collected from general cultivation and self-pollinated for them. Then those off types were crossed with the original variety to study the extent of the effect of genetic purity on those types. One of the most important findings in this study was that all the off-types gave higher values in plant height compared to the original variety Giza 94. The plant height ranged from 151- 202.8 cm Also, one of the most important trait that was affected was the (lint percentage), as most off types gave values less than original variety which ranged from 2929.99- 40.02.. Fiber color was affected, most of the off types were given a cream color, in contrast to the original type, which was white. The results also showed that the softness micronare of the fibers changed, as they became more coarse. This trait is very important in spinning and weaving operations. As for the fiber length character, the results showed that a small number of off types gave values that were lower than the original variety, and most of the hybrids gave values equal to or slightly longer than the original variety. In general most of off-types gave characteristics contrary to the original variety and these plants must be uprooting from seed production fields to maintenance the genetic purity of the variety under commercial scale.