Current taxonomic data define 15 virus families, containing an estimated 500 recognised mammalian virus species. Since many distinct strains have been isolated from each virus species, we estimate that more than 10,000 viruses are distributed globally in small laboratory collections. Many of these could be lost to science if they are not brought together in a co-ordinated high quality collection. The network of EVA laboratories represents an extensive range of virological disciplines and currently holds approximately 50% of the 500 recognised species within the EVA collection. Moreover, through their own local networks they can access the collections of viruses held in small laboratories. The ultimate aim of EVA is to coordinate these collections to produce the largest library of authenticated, quality controlled and available viruses in the world. EVA will therefore "provide a wider and more efficient access to and use of" the virus collections. Partner laboratories have been selected according to the following criteria: extent and relevance of virus collections, capacity to isolate new viruses; recognised high calibre; high quality of associated research; record of achievement in meeting targets; experience of working to standard protocols. EVA as a quality assured virus collection will have the important mission to provide this unique resource, resulting from the merging of well established infrastructures existing in Europe, to service science, the environmental and public health authorities, the needs of the pharmaceutical industry in developing new technologies for disease control, and provide material for teaching and training purposes.