We investigated the molecular weight distributions of cellulose chains of developing cotton fiber from Gossypium hirsutum L. Cellulose, a polymer, comprises ca. 96% of the dry weight of cotton fiber. The molecular weight of a biopolymer is related to the kinetics of the biosynthetic process and influences the mechanical properties of the polymer. Bolls from plants grown under greenhouse and field Conditions were sampled from ten days post-anthesis until maturity. The polymeric technique of gel permeation chromatography was employed. New methodology for analysis of cellulose from cotton fiber without derivatization has been developed. Primary wall formation and secondary wall deposition were monitored. In this preliminary report, cellulose molecular weight distributions of samples from Texas Marker-I and four mutants reflect differences in normal and altered fiber characteristics.