Editors' Summary: As the increased use of automobiles in the United States has offset reductions in auto emissions, legislators and regulators have sought new ways to address air pollution from cars. As part of that search, they have devoted greater attention to the regulation of fuels. This Article analyzes the current federal fuels program and the regulatory and legislative developments that led up to it. The Article begins by discussing the regulation of fuel additives, which resulted in the elimination of lead from gasoline. It then discusses EPA's programs to limit gasoline volatility and sulfur content in diesel fuel, which predated the 1990 Amendments to the Clean Air Act and were incorporated into them. It next examines the new fuels programs that the 1990 Amendments require, including a reformulated gasoline program to reduce emissions of toxic air pollutants and emissions that cause summer ozone pollution, and a detergent additives program to prevent deposits in fuel injectors and intake valves. The Article discusses the oxygenated gasoline program that the 1990 Amendments required states to adopt to reduce carbon monoxide emissions in areas where carbon monoxide is a problem in winter, and addresses EPA's enforcement powers under the current fuels program. Finally, the Article explores the future of fuels regulation and concludes that alternative fuels are likely to receive increasing attention.