Invasive predators are one of the causes of population declines of anurans around the world. The American Bullfrog (Lithobates catesbeianus) stands out among these predators. Based on field observations and stomach content analysis, predation on native anurans by invasive Bullfrogs was investigated in two localities of Southeastern Brazil. The spatial variation in predation and similarity in microhabitat use by native species and Bullfrogs were also determined. Anurans of the families Bufonidae, Hylidae, Leiuperidae and Microhylidae were found among Bullfrog prey. The species preyed upon had medium to high similarity with Bullfrogs regarding microhabitat use. Anurans had high relative importance in the diet of adult Bullfrogs from the site where natural vegetation is preserved. Thus, the possible negative impact of predation by Bullfrogs can be more significant on anuran species which use microhabitats similar to those used by the invasive frogs. This impact may also be higher in preserved sites, increasing the necessity of monitoring and controlling the spread of this invasive species to natural areas. However, as factors other than predation are known to contribute toward negative impacts, further studies are required to clarify the status of invasive Bullfrogs in Brazil.