The feasibility of using coproducts from dry grind corn ethanol production as a substrate for the production of soluble fiber was examined. Acid- and base-catalyzed hydrolysis experiments were performed using sulfuric acid and sodium hydroxide to partially hydrolyze hemicellulose content of whole stillage, a precursor to distillers' grains, to soluble fiber. The influences of temperature, reaction time, and hydrolyzing agent concentration on the formation of soluble fiber were studied. Soluble fiber was recovered by precipitation in a 95% ethanol solution. Results indicate that appreciable quantities of soluble fiber may be extracted using either acid- or base-catalyzed reactions. The highest yield of soluble fibers was 13.2 g per 100 g-db of treated whole stillage using one weight percent sodium hydroxide at 80A(0)C for 1 h. HPLC analysis was used to quantify the amount of monomeric sugars which were formed during the hydrolysis procedures.