Scherer's industrial organization model is modified to characterize the grain marketing system. The modified model identifies the important relationships between economic characteristics and the type of grain facilities found in three states; Alabama, Illinois, and Ohio. Multivariate linear discriminate analysis is used to identify the important basic supply, demand, and transportation variables within and among these states. It is concluded that the structural differences among selected grain marketing regions can be explained by regional differences in basic supply, demand, and transportation variables. The findings suggest that Scherer's industrial organization model can be adapted to explain the diverse structure of the grain marketing system in selected states.