I developed acoustic identification methods and studied habitat use in a speciose bat community from southern Italy. I studied echolocation calls from 23 Italian bat species and devised multivariate discriminant functions used for habitat use studies. I described diagnostic Pipistrellus kuhlii social calls. I demonstrated sympatry of Pipistrellus pipistrellus and P. pygmaeus in Italy. I also examined resting frequencies from Rhinolophus euryale and R. mehelyi: juveniles called at lower frequencies than adults. The implications of these findings for acoustic investigations are discussed. Habitat selection at the community level was determined by acoustic surveys. Activity was highest over rivers and lakes. M. daubentonii and M. capaccinii were affected by wind, and temperature influenced Hypsugo savii activity. P. kuhlii, P. pipistrellus and Tadarida teniotis showed no significant habitat preference. Rivers were selected particularly by Myotis bats and Miniopterus schreibersii. Habitat selection by R. euryale was studied by radiotracking. This species selected broadleayed woodland. Urban, open areas and conifer plantations were avoided. The results have clear implications for bat research and conservation in southern Italy and other Mediterranean areas. Acoustic identification by quantitative echolocation and social cgll analysis promises to be a valuable means to investigate habitat use by bats with high intensity echolocation calls in speciose Mediterranean bat communities. Rivers and riparian vegetation need to be adequately protected and managed. Habitats managed or created by humans were also important and should therefore feature in conservation plans. I recommend avoiding the clearance of continuous, large areas of woodland, and not planting conifers. Urbanisation is a threat to R. euryale and other sensitive species, and should be limited in areas of special value for the bat fauna. Linear landscape elements such as tree lines and hedgerows should also be preserved.