In the past several years, high oil and gas prices, instability in many oil-producing countries, and concerns about global climate change have heightened interest in ethanol and other biofuels as alternatives to petroleum products. Reducing oil dependency is a goal shared by the United States and many countries in Latin America and the Caribbean, a region composed primarily of energy-importing countries. In the region, Brazil stands out as an example of a country that has become a net exporter of energy, partially by increasing its production and use of sugar-based ethanol. On March 9, 2007, the United States and Brazil, which together produce almost 70% of the world's ethanol, signed a Memorandum of Understanding (MOU) to promote greater cooperation on ethanol and other biofuels in the Western Hemisphere. The countries agreed to (1) advance research and development bilaterally, (2) help build domestic biofuels industries in third countries, and (3) work multilaterally to advance the global development of biofuels. Many analysts maintain that the United States would benefit from having more energy producers in the region, while Brazil stands to further its goal of developing ethanol into a globally traded commodity. In addition to these economic benefits, some analysts think that an ethanol partnership with Brazil could help improve the U.S. image in Latin America and lessen the influence of oil-rich Venezuela under Hugo Chávez. However, obstacles to increased U.S.-Brazil cooperation on biofuels exist, including current U.S. tariffs on most Brazilian ethanol imports. While some Members of Congress support greater hemispheric cooperation on biofuels development, others are wary of any cooperative efforts that might negatively affect U.S. ethanol producers. The Energy Diplomacy and Security Act of 2007, S. 193 (Lugar), approved by the Senate Foreign Relations Committee on March 28, 2007, would increase hemispheric cooperation on energy. S. 1007 (Lugar), the United States-Brazil Energy Cooperation Pact of 2007, calls for the same hemispheric cooperation groups as S. 193, and directs the Secretary of State to work with Brazil and other Western Hemisphere countries to develop biofuels partnerships. H.Res. 651 (Engel) recognizes and supports the importance of the U.S.-Brazil MOU on biofuels. In the 109th Congress, legislation was introduced that would have eliminated current tariffs on foreign ethanol, but in December 2006, Congress voted to extend the ethanol tariffs through December 31, 2008 (P.L. 109-432). In the 110th Congress, S. 1106 (Thune) would extend those tariffs through 2011, and H.R. 196 (Pomeroy) would make the tariffs permanent. This chapter discusses the opportunities and barriers related to increasing U.S. cooperation with other countries in the hemisphere on biofuels development, focusing on the U.S.-Brazil agreement. For more information, see CRS Report RL33290, Fuel Ethanol: Background and Public Policy Issues, and CRS Report RL33693, Latin America: Energy Supply, Political Developments, and U.S. Policy Approaches. © 2009 Nova Science Publishers, Inc.