A crucial debate is under way concerning the public's participation in biotechnology decision-making processes. This study, concerning the policy process around xenotransplantation (XTP) in Latvia and Sweden in the period 1970–2004, focuses on how scientific experts and politicians view the public and the public's participation in the process of developing policy regarding XTP. Drawing on interviews with actors involved in XTP in each country, we analyse and explain the inclusion and exclusion of publics in policy decision-making processes. In particular, we highlight the significance of the role of scientists and politicians in generating discourses which exclude the public from participation in policy decision-making.