A survey of the calicioid lichens and fungi of Japan based on collections made by G. Thor during 1994 to 1999, and additional herbarium material is given. Bunodophoron and Sphaerophorus are not revised, but included by summarizing literature reports. 50 species are accept ed as recorded from Japan, most of them restricted to old-growth, humid, boreal to temperate conifer ous forests. The genus Sclerophora is reported from Japan for the first time. One species, Calicinin muriformis, is described as new, and 23 species are reported as new to Japan: Calidum chlorosporum, C. salicinum, Chaenotheca Chlorella, C. trichialis, Chaenothecopsis asperopoda, C. brevipes, C. consociata, C. debilis, C. irregularis, C. nana, C. pusiola, C. rubescens, C. sanguinea, C. viridireagens, Mycocalicium albonigrum, Phaeocalicium compressulum, Sclerophora amabilis, S. coniophaea, S. nivea, Sphinctrina leucopoda, S. turbinata, Stenocybe pullatula, and S. septata. Cali dum Japonicum and C. nipponense are taxonomic synonyms of C. chlorosporum. Calidum sub- quercinum f. dispersum of C. lenticulare, Mycocalicium Japonicum of Sphinctrina tubaeformis, and Pyrgillus boninensis of P. javanicus. Lectotypes for Calidum Japonicum, C. subquercinum, C. sub- quercinum f. dispersum, and Mycocalicium japonicum have been designated. Three earlier reported species, Calidum viride, Chaenotheca gracilenta and Stenocybe major, are excluded from the Japan ese lichen flora since the reports were based on misidentifications. Most of the species are antitropi- cal or have a Northern Hemispere temperate distribution. All species of calicioid lichens and fungi previously reported from Japan are included and references to earlier publications are provided. Keys to the taxa are presented, and short descriptions, diagnostic features, and notes on distributions are in cluded. Calicioid lichens, fungi, Japan.