HIV treatment as prevention is an emerging biomedical prevention approach that seeks to utilize routine HIV testing, linkage to and engagement in HIV care, and the consumption of antiretrovirals in order to suppress individuals’ viral loads, greatly reducing or eliminating the risk of onward transmission of HIV. Drawing on interviews with HIV scientists, policymakers, clinicians, and leaders in HIV community advocacy, ethnographic field work at three global HIV scientific meetings, and extant narrative, visual and material data, this multi-sited study explores the emerging professional discourses that are co-constitutive of HIV treatment as prevention. Through an inductive process of data collection and analysis, four broad analytic problem spaces emerged: the reconfiguring of HIV risk discourses through pharmacological non-infectiousness, the transformations in biomedical surveillance practices as well as subjectivities via a prioritization of viral suppression and viral load monitoring, and the construction of antiretrovirals themselves as technoscientific ‘things’ which both potentiate and disrupt their own use as prevention technologies, in particular, via an anticipatory orientation to the future. This project contributes to work on biomedicalization, particularly on theorizing about transformations of risk and surveillance practices, subjectivity and forms of biomedical citizenships, as well as work on anticipation, notably on the creative effect of biomedical technologies and imagined futures.