Micrurus diana is a rare coral snake species poorly represented in museum collections. Based on two recently identified specimens, we report its occurrence for the first time in Brazil and for the Bolivian Yungas, substantially extending its known range. In addition, we also extend the limits of its known morphological variation, based on examination of 11 specimens. Our findings revealed the need of a better characterization for M. diana, and the need of preservation efforts for this species and its habitat in Brazil.