The world market for cotton is increasingly sensitive to fiber length. With most of the world spinning infrastructure dedicated to ring spinning, it is necessary to have a minimum of 35 staple cotton. Therefore preservation of and measurement of cotton fiber length at the gin becomes increasingly important. Real-time fiber length measurement can facilitate ginning decisions to preserve lenght and thereby preserve value. In 2005, the initial concept was tested at a the USDA Stoneville Ginning Laboratory and a commercial gin and reported on at the 2006 Beltwide Conference. For 2006 season, based on the experience from the 2005 season, an on-line length measurement module was designed, built and installed at a commercial gin. Data were collected to evaluate this uniquely designed on-line lenght measurement.