Cyanoprokaryotes and other microorganisms form biofilms on the stone surfaces. In 4 quarries of rapakivi granites in southern Finland, we have sampled 7 types of communities from the granite surface. The aim of the study is to determine the species composition and ecological characteristics of cyanoprokaryotes in various biofilm types on the rapakivi granite surfaces in southern Finland. During the study on the surface of rapakivi granites a variety of cyanoprokaryotes was described (54 taxa). The Leptolyngbya is the most diverse genus in which 8 species are noted (15% of the detected diversity). The species composition of biofilms, differing in color, is heterogeneous. There are both common for all types of biofilm taxa, and specific for each type of species. The characteristics of life forms of cyanoprokaryotes are discussed.