Urban parks offer refuge for numerous animal species, and some of these parks represent the remaining fragments of native forests. We evaluate the diversity and composition of epigaeic ant species (Hymenoptera: Formicidae) in urban parks located within the Atlantic Forest biome (Centenial Park, Leon Feffer Park and Villa Lobos Park). For our collections, we placed pitfall traps along 100-m line transects in areas both accessible and inaccessible to the public. A total of 46 species distributed in seven subfamilies were collected. The number of species did not differ among park areas, but the ant communities themselves differed. Native species, such as Strumigenys denticulata and S. louisianae, were collected in the most preserved natural areas in the parks. Generalist species composed the richest guild and were primarily found in areas with public access. Wasmannia auropunctata, Brachymyrmex heeri, Solenopsis sp. 2, and Solenopsis sp. 3 were classified with high value as biological indicators.