An econometric model was developed to represent the structural relationships of the U.S. cotton sector. The simultaneous equation model consisted of six endogenous variables including the domestic mill use of U.S. cotton, the farm price and the domestic mill price for cotton, domestic cotton inventories, U.S. exports to non-Communist countries, and the world price for U.S. cotton. Elasticities were estimated from the model for the domestic mill use of cotton with respect to the domestic cotton price and the polyester price, and for cotton inventories with respect to the loan rate and the domestic cotton price. Elasticities were also obtained to estimate the effects of world price, exchange rates, and export financing on U.S. cotton exports. These elasticity estimates when compared to earlier estimates indicated important changes in the cotton sector since the 1960's.