The development of international health from a historical point of view has undergone major advances in recent times and constitutes a substantial part of the current agenda for historians of medicine. Within this framework, and focussing on a specific case study (international responses to poliomyelitis outbreaks in the 20th century), we explore the main actions and achievements of agencies such as the WHO and other private and international scientific organizations. Furthermore, this paper seeks to identify the Spanish presence and absence in these activities, their causes and consequences.