In the bat genus Carollia. C. brevicauda and C. perspicillata are the most abundant and widely distributed in South America; also, their distributional ranges are almost completely overlapped. Because these species are morphologically very similar, they are frequently misidentified. The aims of this study were to determine the morphological and morphometric differences of C. brevicauda and C. perspicillata. For that reason, I employed a detail morphological assessment and several multivariate morphometnc tools. I evaluated 26 normally cranio-dental variables in 375 adult specimens from Perúvian and Ecuadorian populations. In addition, 54 specimens of C. benkeithi, C. manu: and Carollia sp. were included for comparisons. I found that C. brevicauda and C. perspicillata are differentiated by 28 discrete characters, and are significantly different in 25 morphometnc variables. Also, C. brevicauda, C. perspicillata, and C. manu are clustered in a different group from the group of C. benkeithi and Carollia sp. My results complement previous studies adding several characters that confidently differentiate C. brevicauda from C. perspicillata', which needs to be tested in other regions.