The fair, reliable and rapid international sharing of pathogens and related benefits—which we refer to here as pathogen- and benefit- sharing (PBS)—is critical for protecting global public health, particularly in the event of outbreaks of infectious disease. This research project was motivated by the need to increase understanding of current practices in PBS and identify workable solutions for their improvement. We conducted 86 interviews with experts involved in PBS internationally (n=53), during Liberia’s 2014–16 Ebola epidemic (n-20) and during Brazil’s 2015–16 Zika epidemic (n=13). We triangulated our interview data with quantitative data on influenza virus shipments from the Influenza Virus Traceability Mechanism (IVTM) and 26 Material Transfer Agreements (MTAs). Respondents expressed significant concern around the incoherent global governance of PBS, particularly in light of the coming into force of the Nagoya Protocol on Access and Benefit-Sharing in 2014. Pathogen-sharing relied heavily on interpersonal relationships of trust and was not reliable during emergencies, although such sharing occurred regularly outside of outbreaks. Benefit-sharing practices varied widely, with a broad range of understandings regarding what “benefits” could or should mean concretely. Power disparities between stakeholders shaped which pathogens and benefits were shared, with whom and on what terms and conditions, with the security and economic value of both pathogens and benefits escalating rapidly during emergency outbreaks. Our research found no single solution supported by a critical mass of stakeholders, but enough consensus on key principles for a small representative group of stakeholders to start the process of clarifying international normative frameworks for PBS governance. Further case studies are needed on PBS in specific outbreaks, the kinds of benefit sharing arrangements that have been implemented, as well as studies on PBS practices in plant and animal health.