The Intergovernmental Panel on Climate Change (IPCC) recognizes the use of biofuels as alternative energies as a possibility to provide large reductions of GHG emissions. However, according to the United Nations, biofuels could only serve as an instrument to mitigate the climate change problem and enhance energy security if its production is held under careful strategies and appropriate regulations, expressed thus by the use of certificate schemes. The European Union under its new proposal for a directive on the promotion of the use of renewable energy from renewable sources proposed a sustainability certificate for biofuels. Due to the fact that all 27 EU-Members as well the European Communities form part of the World Trade Organization, the sustainability criteria proposed must be in compliance with the WTO rules. The book will examine some polemic aspects regarding the sustainability criteria proposed, using, basically, the following agreements: Agricultural Agreement (AoA); Subsidies and Countervailing Measures (SCM) Agreement; General Agreement on Tariffs and Trade (GATT); and Technical Barriers to Trade (TBT) Agreement.