International trade encourages innovation, boosts development, reduces poverty, creates new markets, enhances competitiveness, improves product quality, and expands the consumer choice set. This dissertation is composed of three papers examining barriers to agricultural trade. The first two papers examine the impact of tariff and non-tariff barriers to agricultural trade while the third paper investigates China's domestic agricultural and international trade policies in order to promote U.S. market access in China. The first paper investigates how trade liberalization expands the range of products available for import and consumption. A multinomial logit framework of unordered export categories is developed: no trade margin, disappearing margin, intensive margin, and extensive margin. The findings of this paper suggest exporters gain from tariff reductions because they can establish new product relationships with the U.S. and enhance their U.S., and potentially global, supply chains. In addition, if consumers value variety in consumption, the extensive product margin results can be viewed as a positive welfare gain for U.S. agri-food consumers. The second paper focuses on non-tariff measures (NTM), which have significant implications for agricultural trade and food marketing. This paper focuses on maximum residue limits (MRLs) for pesticides and their trade restricting nature on U.S. fresh fruit and vegetable trade under the Trans-Atlantic Trade and Investment Partnership (T-TIP) and the Trans-Pacific Partnership (TPP). Specifically, this research develops a bilateral index to measure the stringency of destination market tolerances for pesticide residues relative to those faced in the United States. Using a Heckman two-step model, the results shed considerable light on existing regulatory heterogeneity, which has important implications for policy to focus on increasing compatibility of NTMs across trading nations. The third paper examines China's evolving agricultural and trade policies and discusses the potential impact on U.S. exports to China. China's agricultural imports, and policies affecting those agricultural products, have important implications for the U.S. as the leading export supplier to the Chinese market. China's price support programs, aimed at improving food security and Chinese farmers' incomes, increased domestic prices. This created a gap between domestic and international prices that led to excessive Chinese stockpiles. In response, China implemented respective target prices for cotton and soybeans, eliminated the price support for corn, and continues to introduce new policies. / Ph. D.