Sixty-one studies of the diets of 15 species of bats found in the British Isles are reviewed. Fourteen studies describe the diets of more than one species. Barbastella barbastellus and Plecotus spp. eat mainly Lepidoptera. Eptesicus serotinus takes mainly Coleoptera, but feeds on a wide range of prey, found in several habitats. Rhinolophus ferrumequinum hunts mainly Coleoptera and Lepidoptera by hawking, gleaning and perch hunting. Myotis bechsteinii takes mostly woodland families of Diptera and Lepidoptera. The remaining nine species eat mainly Diptera. Myotis nattereri feeds almost entirely on diurnal Diptera, gleaned from their nightly resting places. Rhinolophus hipposideros and Myotis mystacinus take mostly swarming crepuscular Diptera by hawking, probably near water and in damp wooded areas; both also glean. Myotis brandtii feeds on Diptera by hawking and gleaning; Nyctalus noctula by hawking. Myotis daubentonii, Pipistrellus spp. and Nyctalus leisleri eat many aquatic Diptera, and may therefore be expected to feed close to freshwater habitats. M. daubentonii hunts by trawling aquatic Diptera from the surface of water.