EQUIDS AND GOMPHOTHERES FROM THE LATE PLEISTOCENE OF SOUTHEASTERN OF BUENOS AIRES PROVINCE. The fossil mammal localities of El Conglomerado, Cascada Paleolama, and Rocas Chicas (Buenos Aires Province, Argentina) are poorly known. This paper describes the best-preserved specimens of equids (Perissodactyla) and gomphotheres (Proboscidea) stored at the Municipal Museum of Natural Sciences of Monte Hermoso city. The comparative study with other horses and gomphotheres, mainly from different localities of South America, mostly Argentina and Brazil, allowed to identify them as Hippidion principale (Lund), Hippidion devillei (Gervais), Equus (Amerhippus) neogeus Lund, and Stegomastodon platensis (Ameghino). A sample of S. platensis enamel of M2 from El Conglomerado was dated by AMS ¹⁴C 17,600 ± 135 years AP, while a sample of E. (A.) neogeus enamel of M1 from Cascada Paleolama gave an age of 14,020 ± 60 years AP. The data presented here are consistent with a lapse of time dominated by fauna adapted to arid and cold conditions.