A five year collaborative effort was undertaken at both the Cotton Quality Research Station and the Southern Regional Research Center to assess leading cotton varieties. The two locations independently measured fiber properties for the same cottons for five years. The fiber from each year was processed into yarn at the Cotton Quality Research Station in Clemson, SC. The resultant yarns were tested at both the Cotton Quality Research Station and the Southern Regional Research Center. The first three years' cotton fiber was also processed at the Southern Regional Research Center. The relationship between fiber and yarn properties is studied over the course of the collaborative project. The project was designed to evaluate the leading varieties from various geographic areas of cotton production over a number of years. The extent of the processing and testing was intended to help alleviate limitations in previous studies of this type. A large number of varieties were tested during the course of the study. The results of the study contributes to the understanding of the fiber to yarn relationship.