This chapter explores two different systems of research oversight in recent Brazilian history: the bureaucracies of the twentieth and twenty-first-century Brazilian state, and approaches developed by A’uwẽ (Xavante) aldeias over the same period in Pimentel Barbosa Indigenous Land. Focusing primarily on genetics-based research, Dent develops the concept of bureaucratic vulnerability. She argues that the way some geneticists have interpreted state regulatory systems regarding biosamples creates additional risks for Indigenous people under study. At the same time, Indigenous groups are placed in a bureaucratic double bind, where non-Indigenous experts are called on to justify and validate their claims in the eyes of the state. The protectionist state regulation contrasts with relationship-based practices that A’uwẽ interlocutors have developed over repeated interaction and years of collaboration with a group of anthropologists and public health researchers. Specifically, A’uwẽ have responded to the dual and interrelated challenges of recognition under a colonial state and the management of outside researchers through the careful modulation of researchers’ affective experience of fieldwork, working to create enduring relationships and mutual obligation.