Xenotransplantation (XTP; animal-to-human transplantation) is a controversial technology of contemporary scientific, medical, ethical and social debate in Australia and internationally. The complexities of XTP encompass immunology, immunosuppression, physiology, technology (genetic engineering and cloning), microbiology, and animal/human relations. As a result of these controversies, the National Health and Medical Research Council (NHMRC), Australia, formed the Xenotransplantation Working Party (XWP) in 2001. The XWP was designed to advise the NHMRC on XTP, if and how it should proceed in Australia, and to provide draft regulatory guidelines. During the period 2001-2004, the XWP produced three publicly available documents one of which, ‘Animal-to-Human Transplantation Research: A Guide for the Community’ (2003), was specifically designed to introduce the general public to the major issues and background of XTP. This thesis examines XTP in Australia as guided and influenced by this community document. Explicitly, drawing upon actor (actant)- network theory, I will reveal the Australian XTP network and explore, describe and explain XTP problematisations and network negotiations by the enrolled actants on two key concepts and obligatory passage points - animals and risk. These actants include those providing regulatory advice (members of the XWP and the associated Animal Issues Subcommittee), those developing and/or critiquing XTP (official science and scientists), and those targeted by the technology (people on dialysis, with Type-1 diabetes, Huntington’s disease, Parkinson’s disease, pre-or post-human-tohuman transplantation, and their partner/spouse). The stories are gathered through focus groups, semi-structured interviews and document analysis. They reveal ambiguous and sometimes contradictory stories about animals and risk, which influence and impact the problematisations of XTP and its networks. Therefore, XTP mobilises tension; facilitating both support and apprehension of the XTP network and its construction by both the sciences and the publics.