This paper explores optimal biofuel subsidies in a general equilibrium trade model. The focus is on the production of biofuels such as corn‐based ethanol, which diverts corn from use as food. In the small‐country case, when the tax on crude is not available as a policy option, a second‐best biofuel subsidy may or may not be positive. In the large‐country case, the twin objectives of pollution reduction and terms‐of‐trade improvement justify a combination of crude tax and biofuel subsidy for the food exporter. Finally, we show that when both nations engage in biofuel policies, the terms‐of‐trade effects encourage the Nash equilibrium subsidy to be positive (negative) for the food exporting (importing) nation.