This article explores the prospects for transparency to be a transformative force in global biosafety governance. It analyzes whether information disclosure can further a right to know and choose, and hence facilitate oversight over transnational transfers of genetically modified organisms (GMOs). It examines the question of “Whose right to know what and why?” with regard to GMOs in the agricultural commodity trade in relation to the global Cartagena Protocol on Biosafety. I argue that the limited disclosure obligations in this global context follow rather than shape market developments, and that complex infrastructures of sampling, testing and detection are required to put disclosed information to use. If so, rather than a normative right-to-know of importing countries, a competing norm of caveat emptor (let the buyer beware) prevails. I conclude that the potential of transparency to empower remains unrealized, particularly for the poorest countries most reliant on globally-induced disclosure.