This study aimed to utilize data of recent studies of bats surveying in the Atlantic Rainforest to evaluate the degree of knowledge of bat distribution in this biome. Data of new records or range extension of species published between 2010 and 2013 were compared among Brazilian biomes. We also utilized a case study in the Paraná State coastal area, southern Brazil, which was considered of low priority for bat inventories but had new records reported recently. The Atlantic Rainforest showed the highest number of papers with new information about bat distribution in Brazil. The number of bat species for this biome reaches 117. In the past 10 years, 11 new records have been reported for the Paraná State coastal area, increasing the bat richness by 33%. Our findings suggest that we do not know sufficiently the bat distribution across the Atlantic Rainforest. In such a hotspot for biodiversity conservation, it may be dangerous to establish low-priority areas for inventories, especially when an almost unique and biased survey method has been used.