ABSTRACT: Across the world, people living with HIV and AIDS (PLHA) face investigation, prosecution, conviction, and punishment if they transmit HIV to another person, expose others to the risk of HIV acquisition, or fail to disclose in advance their HIV positive status. This article seeks to explain why limiting the criminalisation of HIV is important and necessary; identifies some of the ways in which it has been, and might be, limited; and, finally, offers some reflections on whether there exists a principled limit to decriminalisation arguments (ie whether there are cases which, even if the general principles underpinning decriminalisation is accepted, justify state punishment). Drawing on recent international policy guidance, current scientific knowledge about HIV prevention and treatment, and research on the impact of criminalisation of PLHA, the article argues that decriminalisation is critical to eradicating HIV and should be a public health priority, that biomedical advances in prevention and treatment will assist the decriminalisation project but are insufficient in the absence of legal and criminal justice practice reform.