Concrete was the principal building material since the beginning of the 20th. century, and the Buenos Aires Province as well as the rest of Argentina were no exceptions. For instance there are some “art-deco” buildings now appreciated and protected as a local heritage. Some of these buildings are colonized by lichens as well as other structures such as dams and road bridges, but were not studied until recently. Therefore,the aim of the present paper is to offer a list of lichens found up to now on mortar and concrete in the Buenos Aires Province that were collected and identified when these structures were inspected. The samples were collected mainly in the central and SW part of the province as well as the southern coast of the Rio de La Plata. These regions have important climatic differences but lichens don´t seem to be influenced by them. Substrate porosity and water retention seem to be more important for lichen colonization. However, some species were collected only in the central part of the Province, but this can only be regarded as a trend. There are 22 species: 17 crustose (Acarosporaceae, Candellariaceae, Lecanoraceae, Teloschistaceae and Verrucariaceae) and 5 foliose(Physciaceae and Teloschistaceae). The most frequent and widespread is the crustose species Caloplaca citrina (Teloschistaceae). Crustose species are also known from Europe. On the other hand, foliose species are restricted to South America. Although no new species were found , the crustose species Sarcogyne pruinosa and Staurothele catalepta are recorded for the first time for Argentina. This list cannot be considered as conclusive. More extensive sampling of other regions of the Province, specially the coastal and the arid zone of the south is needed, as well as microhabitat studies to improve the knowledge about the ecology of these species.

Key words: Argentina, biodeterioration, Buenos Aires, concrete, lichens