Corn, the most widely produced feed grain in the United States, accounts for more than 90% of the total value and production of feed grains. It is also used for food, industrial materials, and fuel ethanol production. Distillers grains, the major coproduct from ethanol manufacturing, are used as livestock feed. There are, however, other potential options, including value-added food, industrial, chemical, and energy applications. Fractionating distillers grains into concentrated streams of protein, fiber, and fat may be key to facilitating these types of utilization. Previous studies on other products have shown that fractionation is a promising mechanism for extracting valuable components and nutrients from various food, biological, and organic streams. There are many mechanisms by which materials can be fractionated, including size classification, air classification, and aqueous extraction. The goals of this study are to review these techniques for a variety of industries and products, as well as to discuss what has been accomplished to date for ethanol coproduct materials. The information discussed here will be helpful for those interested in fractionating various residue streams, including distillers grains.