Dentaries of 6 species of Myotis from eastern North America were analyzed, using landmark-based geometric morphometrics, and were distinguished with 83.3% accuracy, although sexes were poorly discriminated using this technique. Fossils of Myotis from Bat Cave, KY, were studied in an attempt to identify these specimens to species level. Southeastern Bats and endangered Indiana Bats dominated the fossil sample, with some Eastern Small-footed Bats and endangered Gray Bats. Such results demonstrate the ability to differentiate Myotis from historic and prehistoric sites and provide a tool for researchers to understand and potentially to conserve these species.