Today's Friedrich-Loeffler-Institute, Federal Research Institute for Animal Health, on the Isle of Riems near Greifswald, was founded by Friedrich Loeffler in 1910. It is now the world's oldest virological research establishment. As early as 1898, the pupil of Robert Koch had described the foot-and-mouth disease pathogen as a filterable but corpuscular agent capable of reproduction. Owing to this discovery, Friedrich Loeffler is regarded as one of the founders of modern virology. Against the background of the political developments in Germany, this study deals with the expansion of the institute to become one of the world's leading virology research institutes, its eventful history under the auspices of the Academy of Agricultural Sciences of the GDR and as a nationally-owned enterprise during the period when Germany was divided, the foundation of a West German counterpart in Tübingen as well as the successful integration of the facility into the research environment of the Federal Republic of Germany after 1990.