Western Pomerania, nowadays divided between Poland and the German state of Mecklenburg-Vorpommern, covers an area of ca 50,000 km2. The lichen flora of this region is a rich and comprises 526 species. Distribution maps have been drawn for all taxa. A histogram has also be drawn for each species to illustrate its frequency on different kinds of substratum. The investigated lichen flora comprises many species important from the historical and phytogeographical point of view, mainly atlantic, montane and xerocontinental. In this work the author has put forward suggestions regarding the history of the region's lichen flora in connection with the postglacial changes in the vegetation and climate, as well as with human activities. This work does summarise the negative effects of human pressures on the lichen flora of Western Pomerania and takes up the question of hemerophily in lichens. The spread of some species as a result of human pressure is due mainly to the creation of new substrata (concrete, etc.) and habitats, and to habitat changes. The author has discussed some aspects of the biological basis underlying the expansion of hemerophilous lichens. A number of lichen species may be anthropophytes in Western Pomerania, and some anthro-pophytes in Poland as a whole.