Bacterial a amylases, widely used in the desizing of the gray cotton fabrics, convert the starch present in the warp yarns into glucose, a reducing sugar. An attempt has been made to convert the glucose released by amylases in the desizing process into hydrogen peroxide using glucose oxidase enzymes and use the hydrogen peroxide for bleaching of cotton fabrics, in a single step. Conversion of glucose, into hydrogen peroxide, is influenced by aeration of the reaction bath and concentration of the glucose oxidase. Significant improvement in the whiteness and absorbency, reduction in the extractable impurities and clear surface morphology were also observed in the samples obtained from the one-step process. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 2445-2450, 2012