Abstract - Five hundred and twenty species have been recorded for the fauna of Noctuidae (Lepidoptera) in Serbia (Vasić, 2002). In addition to this, there are the research data for Mt. Durmitor in Montenegro (about 260 species have been recorded for the fauna of Noctuidae in Montenegro). The species Mythimna languida (Walker, 1858), Mythimna congrua (Hübner, 1817), and Mythimna riparia (Rambur, 1829), represent species of the genus Mythimna (Lepidoptera: Noctuidae, Hadeninae) new for the fauna of Serbia and Montenegro. These species were found in the Bay of Kotor or Boka Kotorska (southwest Montenegro). The finding of Mythimna languida represents the northernmost finding of that species in Europe.