Biodiesel has recently drawn attention because of its potential to make an important contribution to national energy security and the environment. However, the rapid growth of biodiesel has raised concerns about biodiesel’s impact on the price level and volatility of agricultural commodities. To address these concerns this research investigates the short- and long-run relationships between agricultural commodity and fuel markets, and finds interdependencies between the two. The causal linkage between biodiesel and soybean prices is very weak, indicating little likelihood of biodiesel triggering another food crisis. In contrast, oil price shocks have major influence on both fuel and agricultural commodity prices.