A study to evaluate the effects of foliar applications of Chaperone on fiber quality properties of first-position bolls in rain-fed grown cotton was conducted at a commercial farm in Nueces Co., TX. Cotton cultivar FiberMax 832LL was planted on April 1, 2005 to a plant population of 50,000 in 30' row spacing. Rainfall amounts were adequate from planting to first bloom, but were deficient from first bloom to first open boll, causing cotton to undergo severe water deficits during most of the boll growth stage. Chaperone treatments were as follows:  5 oz/A at early bloom (EB), 5 oz/A at mid bloom (MB), double application of 5 oz/A (at EB and MB), 10 oz/A at EB,10 oz/A at MB, and the untreated check. The experimental layout consisted of a randomized complete block design with four replications. At the time of early bloom application, plants had 19 main-stem nodes, first position bloom was at main-stem node 9, and the first sympodium was at main-stem node 7, while at the time of mid bloom application (2 weeks after EB), plants had 20 main-stem nodes and the first-position bloom was at node 14. At both application times, 20 plants were tagged in all plots to mark the sympodium with the first-position bloom. After defoliation, first-positon bolls (whole bolls with burrs) produced by 9 consecutive sympodia in all 20 tagged plants were harvested and grouped by sympodium. Bolls grouped by sympodium were ginned after counting the number of bolls and measuring seedcotton mass. Fiber was analyzed using AFIS PRO. Both, fiber mean length (Lw) and upper quartile lengths were longer for mid- plant bolls treated with Chaperone at mid –bloom. Untreated and EB of 5oz/A mid-plant positions produced fibers that were less mature than other treatments.