Lapa Nova is a dolomitic Brazilian show cave. Invertebrate fauna registered for this cave is quite rich and abundant. During two intensive surveys in 2009, 24,482 invertebrate individuals belonging to 187 species were sampled. We found 160 species in April sampling, while in September sampling richness was considerably lower, 102 species, with a remarkable species turnover. In this paper the species richness, abundance and species diversity is presented. The Shannon`s diversity index was 2.79 and 2.87 for April and September, respectively. Although one would expect less variations to be found in the deep cave community (when compared to those located near the entrances), due to higher environmental stability, this was not observed at Lapa Nova cave. This “paradox” is probably due to the intense tourism that occurs in the cave, which imposes “instability” in all sectors, not only in nearby entrance areas. Visitation at the cave probably altered the expected natural distribution pattern, imposing a new organization of the communities, driven by the unstable conditions imposed by cave tourism.