Here, we present the first record of Eptesicus brasiliensis argentinus Thomas, 1920 for the province of Entre Ríos, Argentina. This subspecies was originally described as a full species ( E. argentinus) based on its morphological features that clearly separate it from all other species of the genus. However, it was later treated as a subspecies of E. brasiliensis by Cabrera (1957), a treatment that was followed by all authors until today. Our record raises the number of bat species for the province of Entre Ríos to 21. This locality represents the fourth record for this subspecies in Argentina, after 35 years since the last known record was obtained. Its geographic range is extended by approximately 130 km to the south, which represents the southernmost known record for this subspecies, and a new ecoregion, the Espinal, is added to its distribution.