Myotis grisescens (Gray Bat) and Myotis austroriparius (Southeastern Bat) generally do not utilize similar habitats; however, in areas of range overlap where they both may be captured foraging in riparian areas or observed roosting in caves, it may be difficult to discriminate between them due to contradictory information found in mammal identification guides. In order to find characteristics that can reliably be used to identify these species, we examined museum specimens and live-captured individuals to obtain data on length of toe hairs, point of attachment of the plagiopatagium to the foot or ankle, forearm length, and the presence or absence of notches on the claws of feet and thumbs. The presence or absence of a notch in the claws and forearm length were found to be the most objective methods of identifying these species.