There are 1,001 species of bats, almost a quarter of which are globally threatened. The Chiroptera Specialist Group of IUCN's Species Survival Commission has produced two Action Plans examining conservation issues for all species and detailing recommendations for action to conserve the most threatened species and habitats. These Plans are aimed principally at key decision makers as well as organisations and individuals who are promoting bat conservation issues. The underlying threat to bats is pressure on resources from increasing human populations that leads to the loss or modification of foraging habitats and roosts. Bats frequently have a negative public image that influences the response to the problems of rabies and vampire bats in Latin America and conflicts between bats and commercial fruit growers in other areas of the world. In some areas bats are persecuted because people are ignorant of the life history of bats and their role in ecosystems, while in other areas bats are overexploited for food. There is also a general lack of information about the distribution, status, biology and ecology of many species. This review examines some of the more general issues relating to bat conservation. It provides information on bat faunas of all countries worldwide, and on the most threatened species. It highlights the priority areas where action is needed immediately at a global, regional or national level. It highlights in particular the global importance of islands and caves for bats.