The bioeconomy transition is a double-edged sword that may either address fossil fuel dependence sustainably or aggravate human pressures on the environment, depending on how it is pursued. Using the emblematic case of Brazil, this article analyzes how corporate agribusiness dominance limits the bioeconomy agenda, shapes innovation pathways, and ultimately threatens the sustainability of this transition. Drawing from scholarship on power in agri-food governance and sustainability transitions, an analytical framework is then applied to the Brazilian case. The analysis of current policies, recent institutional changes and the case-specific literature reveals that, despite a strategic framing of the bioeconomy transition as a panacea for job creation, biodiversity conservation and local development (particularly for the Amazon region), in practice major soy, sugarcane and meatpacking conglomerates dominate Brazil’s bioeconomy agenda. In what can be described as conservative ecological modernization, there is some reflexivity regarding environmental issues but also an effort to maintain (unequal) social and political structures. Significant agribusiness dominance does not bode well for smallholder farmers, food diversity or natural ecosystems, as major drivers of deforestation and land-use change (e.g., soy plantations, cattle ranching) gain renewed economic and political stimulus as well as greater societal legitimacy under the bioeconomy umbrella.