During the study of the lichen biota of Shikotan Island, Fissurinainabensis (Vain.) M. Nakan. et Kashiw. was identified on the basis of morphological and anatomical data. It is the first record to Russia both at a species and at genus level. The phylogenetic analysis based on the ITS sequences of the studied specimens supported the close re-lationship with F. insidiosa C. Knight et Mitt. belonging to the subfamily Fissurinoideae. A detailed description of the morphology, anatomy and secondary metabolites of the studied specimens is given. This species was previously known from Japan, Taiwan, and Thailand, and the area is extended to Shikotan Island where are the northernmost localities of the species. Detection of stictic acid might be variable depending on researchers because of the small amount of the substance. It was well detected using HPLC in this study. Differences in the number and size of ascospores in specimens from Shikotan Island and those from Japan described in the literature are discussed. Keywords: distribution, lichen, phylogeny, Russian Far East, Sakhalin Region, stictic acid.