The essays that compose this dissertation investigate the economic distortions caused by subsidies and tariffs under the prism of negotiation and litigation processes at the World Trade Organization (WTO). Chapter 1, Potential Impacts of the WTO Doha Round on the Cotton Sector, assesses the price, production and trade effects of reforming cotton subsidies and tariffs under alternative scenarios. While the WTO Doha Round could have a positive impact on world cotton prices and contribute to the expansion of cotton production and exports in developing countries, the likelihood of such an outcome is dependent on the depth of global subsidy reductions. The poor record of internal policy reforms in subsidizing countries and the failure of the US to comply with WTO recommendations in the US Upland Cotton dispute highlight the importance of trade negotiations in addressing the profound distortions that characterize the world cotton market. Chapter 2, International Experience with Agricultural Export Taxes, analyzes the evolution in the use of agricultural export taxes by developing countries, with a primary focus on Argentina, Indonesia and Thailand. Empirical evidence indicates that export taxes are ultimately selfdefeating. While they may generate government revenue and curb domestic prices in the short run, they shift economic incentives, discourage the adoption of improved inputs, and adversely affect yield and output in the long run. Argentina, in particular, turned a blind eye on comparative advantage and eluded development opportunities by heftily taxing agricultural exports for most of the last 100 years. Finally, Chapter 3, Measurement of Ethanol Subsidies and Associated Economic Distortions: An Analysis of Brazilian and US Policies, is the only systematic, detailed and quantified comparative examination of ethanol support in the US and Brazil. US ethanol support reached US$57billionin2002-2011andwasvulnerabletolitigationundertheWTOdisputesettlementmechanism,asitdepressedworldprices,slashedimports,reducedproductionoverseas,andsignificantlyincreasedtheUSshareoftheworldmarket.Bycontrast,BraziliansupportreachedUS$ 27 billion in the same period and was not susceptible to WTO litigation, as it did not cause adverse effects to the interests of other countries.