Today medical research funded by resourceful commercial companies and philanthropic organizations increasingly takes place in much less resourceful settings across the globe. Recent academic studies of this trend have observed how global inequalities have shaped the movements of this research, and how human subjects who make their blood and bodies available are at risk of exploitation. In Lusaka, people expressed their fears of being used by transnational medical research projects in various idioms of concern. While such concerns were always latent, people were generally eager to join the projects. Concerns were often backgrounded in favor of pragmatic attention to—and active creation of—possibilities that might stretch well beyond the purpose and time limit of individual research projects. The article illuminates how intimately the ambiguities and possible scenarios of exploitation inherent in transnational medical research projects are intertwined with scenarios of possibility.