Caves are considered as ecosystems isolated from the surface in varying degrees. Hypogean habitats are mostly oligotrophic, with discretely distributed nutrients, where chemolithoautotrophic species can be found among the producers. In this case, vital activity is provided due to the nutrients of endogenous genesis. Of particular interest are the cavities, which were completely isolated from the surface impact for a long time. As a consequence, unique landscapes and mineral environments were formed in such cavities. An example is given by Taurida Cave, located on the Crimean Peninsula (Piedmont Crimea) and discovered during the construction of Taurida Highway. Samples of sediments were taken right after opening the cave in July 2018. For the cultivation of bacteria andmicrofungi, standard media, extracts from substrates were used. The number and biomass of microorganisms were determined by luminescence microscopy. Chemical composition of the main and trace elements of the cave deposits samples was determined by XRF WDS spectrometer. As a result, a difference in the number and biomass of microorganisms in different parts of the cave was revealed. The main contribution to the biomass of microorganisms is made by actinomycetes and microfungi. The bacteria were dominated by gram-positive bacteria of the genera Bacillus, Arthrobacter, Micrococcus. Among actinomycetes, species of the genus Streptomyces predominated. The species of microfungi Penicillium chrysogenum, Trichoderma sp., Aspergillus sp. were identified, Penicillium janczewskii dominated. The high abundance and biomass of microorganisms in the substrates of the cave may be related to the summer sampling period. © 2020 All Rights Reserved