Geoffroy’s cat is the most abundant felid of the temperate Neotropics. We investigated which factors influence its persistence in one of the most threatened biomes in Brazil, the Pampas. Our study area was a mosaic of open-grassland with pasture, croplands and riparian vegetation. We recorded 516 camera-trap images of Geoffroy’s cat and nine individuals were captured using box-traps. Of those, eight adults were radio-collared (5M and 3F), and monitored through VHF telemetry for a cumulative period of 16 months (434 locations). One male was killed by dogs and a female was poisoned, possibly a result of human conflict from preying on chickens. Despite these disturbances, density estimation using SECR ranged from 34.54 ± 13.51 (SE) to 41.78 ± 16.12 individuals 100km-², reasonable in comparison to other areas. Even though considered an open area species, our study population selected significantly more riparian vegetation (D = 0.45, 95%Kernel; D = 0.48, 95%MCP, P < 0.01), and avoided open grassland (D = -0.59, 95%Kernel; D = -0.51, 95%MCP; P < 0.01). It is noteworthy that the protection of riparian vegetation is required by national law. Hence, this habitat may provide additional shelter for Geoffroy’s cats. This population was nocturnally active (Z = 8.03, P < 0.01) and showed a slight difference between seasons (∆4 = 0.79 CI 0.71-0.85), increasing nocturnal activity during spring-summer. In this study of Geoffroy’s cat in Brazil, we have produced results that can contribute to the design of conservation management actions for the species in this threatened biome.