Numerous collections representing 183 species of lichens, ascomycetes and licheni- colous fungi are reported from gatherings made in Hong Kong in July 2000, mainly on Lantau Island. These include 9 species which are described here as new to science: the lichenized ascomycetes Ani- someridium tetrasporum, Biatorella saxicola, Ocellularia palaeoamplior, Ramalina seawardii, Ra- malina throwerae, the non-lichenized corticolous ascomycete Granulopyrenis seawardii, the licheni- colous ascomycete Obryzam striguloides, and the lichenized hyphomycete Milospium planorbis, one of the very few lichenized hyphomycetes known. It is argued that Reichlingia leopoldii similarly rep resents a lichenized hyphomycete rather than a lichenicolous fungus on an unknown host. The genus Campsosporiella is synonymized with Anisomeridium and the species Campsosporiella deightonii with Anisomeridium throwerae. In addition, 42 species are newly recorded for Hong Kong, of which 38 are also new to China, 7 new to Asia and 4 new to the Northern Hemisphere. Aptroot A. & Sipman H. J. M. (2001): New Hong kong lichens, Ascomycetes and lichenicolous fungi. - Journ. Hattori Bot. Lab., 91: 317-343. jph Anisomeridium tetrasporum sp. nov., Biatorella saxicola sp. nov., Granulopyrenis seawardii sp. nov. (non-lichenized), Milospium planorbis sp. nov., Obryzum striguloides sp. nov. (on Agonimia vouauxii), Ocellularia palaeoamplior sp. nov., Ramalina seawardii sp. nov., R. throwerae sp. nov. (all from Hong Kong only). New to Asia: Anisomeridium albisedum, A. endobryum, Arthopyrenia saxicola, Bacidia egenula, Dimelaena tenuis, Mazosia ocellata, Thelocarpon superellum. New to China: Anisomeridium biforme, Arthonia lividula, A. palmulacea, Bactrospora myriadea, Byssoloma subdiscordans, Calopadia phyllogena, C. subcoerulescens, Chiodecton congestulum, Cryptothecia candida, C. polymorpha, Dimerella pineti, Graphina acharii, G. marcescens, Graphis persicina, Lecidea aurigera, Lichenoconium lecanorae, Lichenostigma cosmopolites, Musaespora gigas (new to Northern Hemisphere), Pertusaria subventosa, P. xanthoplaca, Phylliscum testudineum, Placynthiella icmalea, Porina albicera, P. corruscans, Psora crystallifera (new to Northern Hemisphere), Pyrenula leucostoma, P. nitidula, Sporopodium lucidum (new to Northern Hemisphere), Strigula phaea, Verrucaria pinguicula