The genus Pachycnemia Stephens, 1829 and two species belonging to it: Pachycnemia hippocastanaria (Hübner, [1799]) and Pachycnemia tibiaria (Rambur, 1829) are reported as new for the Bulgarian fauna. Both species are numerous but established in a single locality only. Idaea infirmaria (Rambur, 1833) is new to the Bulgarian fauna, it is syntopic to the species above. Nola ronkayonim Beshkov, 2006 up to now was known only from the type material. Many other species [Pieris ei-gane (Geyer, 1828), Melitaea arduinna rhodopensis Freyer, [1836], Rhoptria as-peraria (Hübner, 1817), Hydraecia micacea (Esper, [1789]), Naenia typica (Linnaeus, 1758), etc.] are new for the Strandzha Mts or for the Black Sea Coast, the rest of the reported species are rare and known from very few localities in the country or were not reported before from Strandzha. Conservation status and the importance of the species reported are presented.