In 1999 large scale, commercial size plots were established at six locations in Mississippi to evaluate the effects of Roundup Ultra herbicide on Roundup Ready cotton varieties. The primary objective was to compare fruiting characteristics, maturity and yield of a Roundup Ready variety treated with Roundup Ultra to the same variety treated with conventional herbicides and not sprayed with Roundup Ultra. Plots were established in Hinds, Yazoo, Leflore, Bolivar and Coahoma counties and represented both hill and delta soils. All plots were located on commercial farms, where they were planted, sprayed and managed by growers and treated consistent with their normal operations.