Sixty six species of lichenicolous fungi are reported from Japan and eight species from South Korea. The new genus Caeruleoconidia is introduced, and four species, Caeruleoconidia ochrolechiae, Diplolaeviopsis japonica, Perigrapha lobariae and Skyttea ochrolechiae, are described as new to science. The new combination Lichenosticta lecanorae is introduced and a neotype designated for this taxon. Buelliella cf. inops, Cercidospora stenotropae, Cladophialophora parmeliae, Endococcus cf. brachysporus, Lichenosticta lecanorae, Micarea inquinans, Minutoexcipula cf. mariana, Protounguicularia nephromatis, Polycoccum hymeniicola, Stigmidium alectoriae and Tephromela campestricola are new to Asia, another 18 species are second reports for Asia. Sixty-one species are new to Japan and eight species new to South Korea. Nephroma is a new host genus for Hainesia aeruginascens and Vulpicida for Muellerella lichenicola. A first synopsis of the lichenicolous fungi of Japan including 95 species is presented, which presumably covers less than 30 % of the total diversity of lichenicolous fungi in that country. Key words: Lichen-inhabiting fungi, taxonomy, biogeography, Asia.