The bats usually inhabit shelters with favorable conditions for fungal proliferation, including pathogenic and opportunistic species. The fungal diversity present on bats is little known and the studies are scarce in Brazil, which only a work has been performed in Cerrado and Pantanal biomes. Therefore, the objective of this study was evaluating the occurrence of filamentous fungi on the rostral region of Molossus molossus in an Atlantic Forest remnant of Brazil. The bats were captured with mist nets installed outside a shelter located in the municipality of Treviso, (28°29'23”S and 49°31'23”W), south region of state Santa Catarina. With a swab sterile moistened in saline solution, samples from the rostral region were obtained from all captured M. molossus individuals. The samples were taken to the laboratory for analysis and isolation in different culture media, followed of identification of fungal through the microculture technique. In total, 15 individuals were captured, which five fungal genus and 19 taxa were identified. Among the taxa registered, Aspergillioides sp.2, (47%), Penicillium sp.1 (33%), Chrysonilia sp. (33%), Cladosporium sp. (27%) were classified as little constant. In terms of abundance, Penicillium sp.1 (34%), Aspergillioides sp.2 (21%) and Aspergillus sp.2 (11%) were the most abundant in the samples. The results showed the occurrence of high diversity fungal in the rostral region of M. molossus in the Atlantic Forest, which is higher than observed in others Brazilian biomes. Some fungal genera found may harbor pathogenic and opportunistic species that need to be identified for preventing potential disease well as for bat conservation projects.