The Paso Otero 5 site is located in the middle basin of the Quequén Grande river (Buenos Aires Province, Argentina). This site is the first recorded Pleistocene-Holocene archaeological context in the grasslands of the Interserrana Bonaerense Area at which extinct megamammals and a ‘fish-tail’ projectile point have been recovered in association from buried soil dated to c. 10,200–10,450 BP.