From late September 2014 to late January 2015, global crude oil prices fell by 51%. Declining crude oil prices triggered a sharp decline in gasoline prices, with a resulting sharp decline in ethanol prices. Since U.S. ethanol is produced primarily from corn starch, these dramatic price changes raise important questions for ethanol producers, livestock farmers, industries that provide inputs to corn production, the transport sector, the petroleum industry, motorists, and other users of petroleum and biofuel products. In this article, we address these questions.