Driven by the expanding production of biofuels, the linkage between the agricultural and energy markets is evolving, and that has changed the market for agricultural commodities dramatically. These developments in agricultural markets consequently shifted the distribution of domestic grains and feeds and the utilization of shipping modes for these agricultural products. As the leading producer of corn, soybeans, and biofuels, Iowa is at the forefront of this shift. Because of the importance of maintaining an adequate state transportation system to accommodate the evolving patterns of grain and biofuel flows, it is important to have current information about grain flows from farms and country elevators to destination markets, along with the information about transportation modes utilized for the shipments. Information about biofuel distribution is also crucial for agricultural and transportation policymakers so that they can provide relevant assistance for this growing industry. This study is designed to meet these needs and to provide updated information on grain and biofuel flows in Iowa during the 2006 and 2007 marketing years.