Freshwater mussels of the Order Unionida provide important ecosystem functions and services, yet many of their populations are in decline. We comprehensively review the status of the 16 currently recognized species in Europe, collating for the first time their life-history traits, distribution, conservation status, habitat preferences, and main threats in order to suggest future management actions. In northern, central, and eastern Europe, a relatively homogeneous species composition is found in most basins. In southern Europe, despite the lower species richness, spatially restricted species make these basins a high conservation priority. Information on freshwater mussels in Europe is unevenly distributed with considerable differences in data quality and quantity among countries and species. To make conservation more effective in the future, we suggest greater international cooperation using standardized protocols and methods to monitor and manage European freshwater mussel diversity. Such an approach will not only help conserve this vulnerable group but also, through the protection of these important organisms, will offer wider benefits to freshwater ecosystems. ; The authors appreciate the extensive work of Wendell Haag and two anonymous reviewers that improved the quality of the manuscript; Arthur Bogan and David Strayer for their assistance and careful thoughts; Marco Paulo Magalhães for help with the GIS maps; Imre Potyó for the photo of Pseudanodonta complanata; the people who took part in the Belarusian data collection especially I. A. Rudakovskiy and V. M. Samoilenko (Belarusian State University), and G. M. Tischikov and I. G. Tischikov (Republican GidroMeteoCenter of Belarus); Marco Bodon and Simone Cianfanelli for valuable information on Italian populations; all the people who provided us with the data included in the French INPN database; Zdravko Hubenov, Dimitar Kozuharov, Lyubomir Kenderov and Ivan Botev for the help with the Bulgarian data collection; and I.N. Bolotov, O.V. Aksenova, I.V. Vikhrev, A. A. Makhrov, P. E. Aspholm for help with the collection and analysis of the Russian data. Financial support was provided by: The Portuguese Foundation for Science and Technology (FCT) and COMPETE funds, project 'CONBI' (Contract: PTDC/ AAC-AMB/117688/2010) and project 'ECO-IAS' (Contract: PTDC/AAC-AMB/116685/2010); The Bavarian State Ministry of the Environment and Consumer Protection through the Bavarian Mussel Coordination Office; The Federal Government of Upper Austria (Department of Nature Conservation), by the Environmental Councilor (Manfred Haimbuchner) and by the European Union; Ministry of Natural Resources and Environmental Protection Republic of Belarus, Belarusian Committee of Ecology grant 288/73 from the Belarussian State University grant 444/50 and from the Ministry of Education and Science Republic of Belarus grant 657/65; The Ministry of Science, Education and Sports of the Republic of Croatia (119-1193080-1231), Hrvatske vode and State Institute for Nature Protection; The Czech Science Foundation (13-05872S) and ESF/MŠMT (CZ.1.07/2.3.00/30.0040); Biotope Consultancy, grants from Muséum National d'Histoire Naturelle à Paris, ATM Barcode and Agence Nationale de la Recherche '6eme extinction'; Polish Ministry of Science and Higher Education grant NCN No. NN304328836; The Russian Foundation for Basic Research, RFBR (grant no. 15-04-05638, 14-04-98801_a) and The Ural Branch of RAS (no.15-12-5-3), President of the Russian Federation (grant no. MD-6465.2014.5). ; info:eu-repo/semantics/publishedVersion