Bat research was carried out in 2012-2013 in the Ujście Warty National Park and in adjacent areas. Bats were caught in chiropterological nets, searched for in winter and summer roosts. Detector listening was carried out and the owls' diet was analyzed for the presence of bats among their prey. In the national park area, 11 species of bats were detected, and together with the Natura 2000 area "Ujście Warty" and the neighbouring areas, a total of 15 species were detected: the Daubenton's bat Myotis daubentonii, Natterer's bat Myotis nattereri, Brandt's bat Myotis brandtii, noctule bat Nyctalus noctula, serotine bat Eptesicus serotinus, common pipistrelle bat Pipistrellus pipistrellus, soprano pipistrelle bat Pipistrellus pygmaeus, Nathusius' pipistrelle bat Pipistrellus nathusii, brown long-eared bat Plecotus auritus, gray long-eared bat Plecotus austriacus, western barbastelle bat Barbastella barbastellus, greater mouse-eared bat Myotis myotis, Bechstein's bat Myotis bechsteinii, pond bat Myotis dasycneme and the parti-coloured bat Vespertilio murinus. The bat fauna of this area is relatively rich compared to other protected areas and presented results constitute an important supplement to the knowledge about the vertebrate fauna of the national park and its vicinity.