Antioquia is a state (department) of Colombia, located in thenorthwestern Andes of South America. Geologically, the northwesternregion of the Western Range in Antioquia and Chocóincludes the fault resulting from the connection between theIsthmus of Panamá and South America. The Occidental andCentral cordilleras in Colombia are characterized by a numberof reliefs, valleys and water basins, containing historicalbiological refuges and endemisms. In this study, we presentthe first species-level checklist of the 255 species (in 64 generaand 14 subfamilies) of ants currently known in Antioquia. Onehundred and fifty-two (152) species had previously been registeredfor the state in different publications. Here, 103 additionalspecies are recognized. Most of these species are distributed inother bioregions of the country as well. Forty-six percent arepresent in the Amazon Province and 36% in the ColombianOrinoco River basin. Less than 3% are found in the arid landsof the Colombian Caribbean area, Guyana, and the ColombianPacific Province, plus the Caribbean islands. Sixty-three percentof the species are shared with Costa Rica. Our checklist constitutesthe largest roster of ants at the species level for a state inColombia to date and constitutes the beginning of the assessmentof ant diversity in Antioquia. Many more field trips arenecessary to gain a better understanding of the ant compositionof this state. The following 13 species are new to the records forColombia: Azteca diabolica, Camponotus amoris, C. eurynotus,C. pachylepis, C. propinquus, C. tonduzi, Cerapachys toltecus,Cylindromyrmex whymperi, Myrmicocrypta urichi, Pheidoleangulifera, Pseudomyrmex lisus, Solenopsis subterranea andTrachymyrmex zeteki.