The polypores of the Helsinki municipal area in South Finland were studied with regard to their microdistributions, host relationships, abundances and economic importance. Altogether 120 species are reported. Five site types were defined, ranging from urban to rural environments: parks proper, tree rows, park forests, forests proper and idle land areas. Distinct differences were found in the species composi ti ons of urban environments (parks proper and tree rows), as compared with more natural wooded areas (park forests and forests proper). Po lypores which prefer urban growth sites (the centric species) are southern in