The influence of temperature and water supply during growth of the cotton plant is under investigation with respect to fiber quality. Cotton (Gossypium hirsutum L., Texas Marker-1) was grown at constant temperature (25, 27.5, 30, or 32.5 C) in a growth chamber with imposition of water stress (ca. 50% of control treatment by weight) from flowering until maturity. Bolls were designated by location zones of top, middle, and bottom according to node position. Tagged bolls were removed at harvest for subsequent analysis of fiber properties and cellulose molecular weight distribution determinations. Strength testing of single fibers individual bolls from plants grown at 25 and 30 C has demonstrated reduction in breaking strength for both the water-stress samples compared to the control at each temperature and for the lower temperature compared to samples grown at the higher temperature. Trends in extension at break values indicate temperature as significant. Dramatically reduced boll production has been observed with plants grown continuously at 32.5 C supporting the observations of previous studies. Molecular composition profiles of the cellulose polymer comprising the cotton fiber demonstrate that populations of cellulosic chains can vary to produce similar strength values in fibers.