Abstract The genus Aedia Hübner (Lepidoptera: Noctuidae) is distributed from Europe through Asia to Oceania, and the larva of Aedia leucomelas (Linnaeus) (so-called “Nakajiro-shitaba” in Japan) has long been recognized as an injurious pest of sweet potato ( Ipomoea batatas (L.)) in Japan and Korea. In this study, we carried out a taxonomic study of the A. leucomelas and its relatives in Japan based on morphological and molecular analyses. The results revealed that “Nakajiro-shitaba” consists of two distinct species: A. leucomelas and A. limitaris (Walker) sp. rev. Therefore, we redescribe A. limitaris and provide diagnostic morphological and DNA barcode data for adults and larvae of the three Japanese Aedia species, i.e., A. leucomelas , A. limitaris , and A. kumamotonis (Matsumura). We also summarize their distribution and host plant information. Furthermore, our study clarified that A. leucomelas and A. limitaris occur sympatrically in Japan at least in some regions, and that larvae of A. limitaris can successfully feed and grow on the leaves of Ipomoea batatas same as A. leucomelas . These findings suggest that previous records of A. leucomelas in Japan may have included A. limitaris , consequently, re-examination of the distribution and life history of A. leucomelas and A. limitaris is required.