This dissertation investigates the construction of the soybean industry in Mato Grosso, Brazil, and the relations between farmers, agribusiness, and the state that have given rise to a model of agricultural production that is suggestive of a new, third food regime. Soybean cultivation began in earnest in Mato Grosso in the 1980, but it was not until the mid-1990s that the state became a significant competitor with the US for soybean export markets. This dissertation argues that the soybean industry in Mato Grosso is structured by a "private international soy regime" consisting of government, corporate, and farmer interests that work to integrate production into global markets, albeit through a contested and contradictory process. The concept of 'food regimes' helps to clarify those contradictions as well as they ways in which this mode of production differs from earlier historical periods. Chapter 2 explores the place of Brazil and Mato Grosso in the global soybean commodity system both historically and analytically. This chapter located Brazil within a chronology of food regime development and decline and argues that the emergence of the Mato Grosso soy sector signals a departure from previous modes of political-economic organization of production. This chapter uses the concept of the "corporate food regime" to highlight the contradictions inherent in this historical moment. Chapter 3 looks in detail at the experience of the food regime on the ground in Mato Grosso through qualitative research with farmers, agribusiness employees, and community members in 5 towns throughout the state. This chapter argues that the category of "agribusiness" must be disaggregated and the experiences of soy farmers themselves taken seriously in order to understand how power is accomplished in a global commodity network governed by a private regime, such as soy. Chapter 4 examines private governance at the global level by investigating Brazil's role in the World Trade Organization and the constitutionalization of market rule. I argue here that various WTO mechanisms allow for and enable the exercise of private authority in ways that are often obscured by the political language of trade negotiations.