Summary: The urgency of global problems related to conservation and sustainable use of biological resources is generally acknowledged. Obstacles to the proper development and implementation of environmental management systems include poor access to reliable biodiversity information. Part of this problem lays in the lack of standardisation in taxonomic reference systems. Other parts of the problem concern the quality and completeness of taxonomic data sets, and the absence of an integrated access to taxonomic information. PESI will contribute to the solution of this impediment by improving the European e-infrastructure through the strengthening of the respective scientific, social, political, technological, and information capacities in Europe, needed for a proper biodiversity assessment. Objectives: Because the correct use of names and names relationships is essential for biodiversity management, the availability of taxonomically validated standardised nomenclatures are fundamental for biological e-infrastructures. PESI is the next step in integrating and securing taxonomically authoritative species name registers that underpin the management of biodiversity in Europe. PESI will integrate the three main all-taxon registers in Europe, namely the European Register of Marine Species, Fauna Europaea, and Euro+Med Plantbase in coordination with EU based nomenclators and the network of EU based Global Species Databases. It is a standards based, quality controlled, expert validated open-access infrastructure for research, education, and resource management. Action plan: PESI defines and coordinates strategies to enhance the quality and reliability of European biodiversity information by integrating the infrastructural components of four major community networks on taxonomic indexing and their respective knowledge infrastructures, namely those of marine life, terrestrial plants, fungi and animals, into a joint work program. This will result in functional knowledge networks of taxonomic experts and regional focal points, which will collaborate on the establishment of standardised and authoritative taxonomic (meta-) data and the development of approaches on their long-term sustain. The organisation of national and regional focal point networks as projected not only assures the efficient access to local expertise, but is also important for the synergistic promotion of taxonomic standards throughout Europe, for instance to liaison with national governmental bodies on the implementation of European biodiversity legislations. In addition PESI will coordinate the integration and synchronisation of the European taxonomic information systems into a joint e-infrastructure following the running initiatives for creation of a Global Names Architecture for the efficient and unambiguous cross-referencing of taxon names, the progress on a joint Internet Platform for Cybertaxonomy with EDIT, and the set up of a common user-interface disseminating the pan-European checklists and associated user-services results.