ABSTRACT: The habitat fragmentation modifies the pattern of animal activity. This study aimed to determine the activity pattern of frugivorous bat species in an urban forest fragment in southwestern Amazonia. The study was conducted from August 2013 to September 2014 with 10 mist nets (9m x 2.5m), opened at ground level throughout all the night and totaling 64,800 m².hour/net. Two hundred and sixty-one captures of bats from 28 species were recorded. The period with the highest capture rate and species of bats was the first period of the night (until 00:00). The species with the highest incidence of catches were, in ascending order, Carollia brevicauda (Schinz, 1821), Carollia perpicillata (Linnaeus, 1758), Artibeus planirostris (Spix, 1823), and Artibeus lituratus (Olfers, 1818). The species of Carollia had activity peaks between the first four hours after sunset; they also showed a reduction of its activities during the subsequent hours. The bats of the genus Artibeus presented a pattern of bimodal activity and they do not seem to respond to the effects of fragmentation, since the pattern of bimodal activity was described for studies in fragments and continuous forest. Thus, we suggest that Artibeus has a high adaptive plasticity, and it is able to exploit the resources offered by the environment. Meanwhile, Carollia has two peaks of activity in continuous forest areas, probably this pattern of activity may be related to the spatial distribution of the resources used by these animals.