Traditional fiber testing methods have focused on the bales of cotton as they are used in the spinning process. Basic fiber properties such as length, strength, micronaire, and color have been analyzed in great detail for the affect on yarn strength. A tremendous amount of data has been generated showing excellent correlations between the HVI measured fiber properties and yarn quality. These prediction formulas and correlations show that HVI properties measured on each bale of cotton can predict certain yarn quality parameters from 50% to 75% of the time. This has lead mills to further investigate the process in an attempt to improve the predicted yarn quality and overall spinning performance in the textile mill. Over the past few years mills have begun to focus on process improvement using the AFIS instrument. The AFIS was designed to measure individual fibers in raw and process cotton. The measurement is much slower than the HVI with each test taking about three (3) minutes, but the results are very detailed distributions. Information from the AFIS provides averages and complete distribution histograms of all measured properties. The focus of the AFIS measurement has been on neps, short fiber content, and trash. We have now taken this instrument with its detailed results into the ginning process. This was done because both the ginning and spinning processes have a large impact on neps, short fiber content, and trash. We also discovered that controlling the process in both the spinning mill and gin have a great impact on the final quality of yarn and fabric. Our investigation focused on the changes in neps and short fiber content in saw-ginned U.S. upland cottons. The results show that there is a wide difference within and between gins on these two fiber properties.