In today's testing of textile fibers, numerous methods have been established to measure fiber length. The global industry is becoming more aware of the impact of length variability on the spinning process, and its affects in subsequent processes. Numerous instruments exist for measuring various length parameters. The focus of this paper is the measurement of Short Fiber Content (SFC), fibers less than 1/2 inch (12.7mm), by the latest generation of the Uster Advanced Fiber Information System Length and Diameter Module (AFIS L&D). Many technical papers have been presented describing the impact of short fibers on the spinning process.1-5 However, we have found in our work around the world that questions still exist about the use of the various length measurements and about AFIS measurements in particular. We hope to clarify these points and make some suggestions for using the AFIS SFC information. Furthermore, an analysis of the SFC by number & by weight of four cotton varieties in both a carded and combed process will be discussed.