This master thesis investigates the relationship between the occurrence and activity of insectivorous bats and insect abundance, as well as various habitat parameters. I collected bat, insect, and habitat data at 82 locations in and near Vienna during the summer seasons 2010 and 2011, respectively, with batcorders and light traps. The statistical analysis revealed no significant relationships between total bat activity, activity of single bat species, and insect abundance. Only the occurrence of Pipistrellus pipistrellus was negatively associated with the occurrence of Coleoptera. The type of water body had no impact on the dependent variables, except for a negative correlation between "Begradigter Hügellandbach" and the occurrence of bat species, particularly Nyctalus noctula and Pipistrellus pygmaeus. Habitat structure was negatively correlated to the activity of P. nathusii/kuhlii, P. pygmaeus, and total bat activity.