Myotis lavali is an insectivorous bat that occurs along the South American Dry Diagonal, extending from the Brazilian Caatinga southward to Paraguayan Alto Chaco. This species was described recently and there is little information about its biology. Herein, we describe the conventional karyotype from three males captured in an arboreal savanna from Vale do Jequitinhonha, State of Minas Gerais, Brazil. The diploid number (2n) and the fundamental number of autosomes (FNa) were 44 and 50, respectively. Its karyotype, in Giemsa staining, is similar to others described for Neotropical Myotis, and it is not useful to identify specimens.