Ants in the genus Dinoponera (Hymenoptera: Formicidae: Ponerinae) are among the largest sized Formicidae of the World. In Brazil Dinoponera has an allopatric distribution, and several species occur in threatened biomes. We characterized karyotypes of the following 4 species: Dinoponera australis Emery, Dinoponera gigantea Perty, Dinoponera lucida Emery, and Dinoponera quadriceps Santschi. Karyotype analysis found that all 4 species have high numbers of small-sized chromosomes (D. australis, 2n = 114; D. gigantea, 2n = 82; D. lucida, 2n = 118/120; D. quadriceps, 2n = 92). A moderate variation in chromosome number was observed among the 4 species, which suggests the occurrence of chromosome rearrangements during karyotype evolution in Dinoponera. An exclusive A^MT chromosome pair was found to occur in all Dinoponera species studied thus far, which we conclude is a probable synapomorphy in Dinoponera.