The grain transportation system has faced many changes in the past ten years. Deregulation of the transportation system has caused a significant"ly different environment within the transportation system. The purpose of this study is to develop a series of models to determine least cost flow patterns for Oklahomaproduced wheat under different assumptions. Each model wil I determine an optimal transportation mode and route for movements of Oklahoma-produced wheat under different alternatives. Results from this study show optimal flows under forty different alternatives. Although the algorithm used in this work does not have sensitivity analysis, the sensitivity of the wheat transportation system in Oklahoma can be determined by looking at the effects of changing assumptions upon results. Before grain handling firms can make longterm capital investments, these firms need to know what flows are optimal and how sensitive these optimal flows are to potential changes. These results should help provide this information to firms in the grain transportation industry.