Abstract Relatively little information has been generated regarding the mammal diversity of Barra del Colorado Wildlife Refuge, Costa Rica. This study assessed relative abundance and activity patterns of some terrestrial mammalian species. We used ten camera traps distributed within the refuge, during 2014. After a total of 1 611 camera trap nights, we identified 15 mammalian species in seven orders and 11 families. The most abundant species were Dasyprocta punctata, Leopardus pardalis, Tayassu pecari, Mazama temama, Pecari tajacu and Tapirus bairdii, while Tamandua mexicana was characterized by its lower abundance. Activity patterns were estimated for eight species, all of which were similar with those previously described in the literature. Further monitoring is required in the refuge in order to increase our understanding of its diversity, information that will be essential for the proper management of the area.