The composition of micromycetes of rocks and deposits of the caves Kinderlinskaya and Oktyabrskaya, located in the Republic of Bashkortostan, Russia, have been studied. The caves are formed in the upper Devonian Famennian limestones. These caves differ significantly in anthropogenic load due to their different accessibility to humans. Kinderlinskaya is a horizontal cave with a large entrance often visited by tourists. It needs special climbing equipment to enter to the October cave as it is situated on the height of 98-meter over the precipice. The study was carried out over the period from 2011 to 2015. The temperature in the caves was at 4-8ºC interval and humidity was from 60 to 100%. Generally 50 sites in the Kinderlinskaya cave (the length of the cave is 8130 m) and 12 sites in the Oktyabrskaya cave (the length is 1523 m)were studied. The sampling was carried out in different seasons, which significantly allowed to increase the detection of micromycetes biodiversity.To identify the species composition of micromycetes authors used a set of standard mediums and extracts from the substrates of the cave. The cultivation of micromycetes was carried out in a wide range of temperatures in order to allocate the largest number of species. Some of the crops were carried out directly in the cave. As a result, 110 species of micromycetes and 16 sterile forms in the cave of Kinderlinskaya and 52 species and 36 sterile forms in Oktyabrskaya were revealed. Species richness of fungi was higher in the Kinderlinskaya cave, due to intense anthropogenic pressures. The same species with high occurrence in both caves were revealed: Penicillium chrysogenum, Alternaria alternata, Mucor hiemalis Mortierella alpina. However, there were 3 dominant species in Kinderlinskaya, while in Oktyabrskaya the number of dominant species was 8. It was found that the number of species on the examined sites in the caves were differed, in the Kinderlinskaya cave the average number of species was 10.3 and in Oktyabrskaya it was 14.5. Micromycetes were extracted from the substrates of caves by cultural methods and for them the connection between the activity of cave visits and the increase in the species diversity has been established. © SGEM2018.