As the renewable fuels industry continues to grow, the quantity of resulting byproducts has expanded in tandem. Currently, these materials are primarily used for animal feed, but at some point will saturate the animal feeds market. Thus, it is necessary to investigate alternative methods and applications by which these coproducts can be utilized. One potential application for these process residues involves plastics manufacturing. Due, in part, to the increasing cost of resins and conventional fillers, alternate fillers have been increasingly sought. Many of these include biological materials such as grasses, bamboo, starch, chicken feathers, soy protein, and cellulose. Not only do these have the additional benefit of improving mechanical properties, but they have the added benefit of biodegradability. Biological fillers have been shown to improve various plastic properties but, in some cases, can actually slightly degrade resulting mechanical properties, such as tensile strength, and ductility. There exists the potential to use fuel ethanol processing coproducts as plastic fillers. To date, however, this has not yet been investigated. This paper reports on preliminary results of a study aimed at determining mechanical and physical properties of plastics filled with these coproducts. Several blends were compression molded and resulting mechanical properties were determined. This information was then used in a theoretical Finite Element Analysis (FEA) model to predict processing behavior and ultimate performance of the coproduct/plastic composite materials. Predicted mechanical properties were then compared with experimental results to refine the model.