The types of species previously placed in Pseudosmittia Edwards and some related genera in the Sasa collection at The National Museum of Sciences, Tokyo, Japan, have been examined. Twentyfour new synonyms are given: Pseudosmittia ogasatridecima Sasa et Suzuki, 1997a is a synonym of P. bifurcata (Tokunaga, 1936); P. jintuvicesima Sasa, 1996, and P. seiryupequea Sasa, Suzuki et Sakai, 1998 of P. danconai (Marcuzzi, 1947); P. mongolzeaea Sasa et Suzuki, 1997b of P. forcipata (Goetghebuer, 1921); P. hachijotertia Sasa, 1994 of P. holsata Thienemann et Strenzke, 1940; P. itachibifurca Sasa et Kawai, 1987, P. furudobifurca Sasa et Arakawa, 1994, P. hibaribifurca Sasa, 1993, and P. (Nikismittia) shofukuundecima Sasa, 1998 of P. mathildae Albu, 1968; P. yakymenea Sasa et Suzuki, 2000a, and P. yakyneoa Sasa et Suzuki, 2000a of P. nishiharaensis Sasa et Hasegawa, 1988; P. kurobeokasia Sasa et Okazawa, 1992a, P. togarisea Sasa et Okazawa, 1992b, P. hachijosecunda Sasa, 1994, P. toyamaresea Sasa, 1996, P. yakyopea Sasa et Suzuki, 2000a, P. yakypequea Sasa et Suzuki, 2000a, Parakiefferiella hidakagehea Sasa et Suzuki, 2000b, and Parakiefferiella hidakaheia Sasa et Suzuki, 2000b of Pseudosmittia oxoniana (Edwards, 1922); P. famikelea Sasa, 1996a of P. tokaraneoa Sasa et Suzuki, 1995; P. ikemaensis Sasa et Hasegawa, 1988, and P. amamiagina Sasa et Suzuki, 1993 of P. topei Lehmann, 1979; P. toyanigra Sasa, 1988 of Camptocladius stercorarius (De Geer, 1776); P. kurojekeus Sasa, 1996 of Prosmittia jemtlandica (Brundin, 1947); and P. tobaunvicesima Kikuchi et Sasa, 1990 of Pseudosmittia guineensis (Kieffer, 1918). Two new combinations are given: Pseudosmittia mongolzebea Sasa et Suzuki, 1997b belongs in Pseudorthocladius and Parakiefferiella yakytriangulata Sasa et Suzuki, 2000a is placed in Rheosmittia. Thirteen species are recognized for Japan. Among these, five species are known only from Japan, one is known from Christmas Island and the Bonin (Ogasawara) Islands (Japan), one from Africa, Okinawa and the Nansei Archipelago (Japan), and one species is Palaearctic and Oriental but in Japan known only from Okinawa. The remaining five species are widespread in the Holarctic with one also being Afrotropical and the others occurring in the Pacific parts of Japan and in Oriental China. Of the two species described as Pseudosmittia from Mongolia, Pseudosmittia mongolzebea Sasa et Suzuki belongs to Pseudorthocladius, whereas P. mongolzeaea Sasa et Suzuki is a synonym of P. forcipata (Goetghebuer). Pseudosmittia tobaunvicesima Kikuchi et Sasa, from Indonesia is a synonym of the Afrotropical P. guineensis (Kieffer). Pseudosmittia bifurcata (Tokunaga), P. jintuoctava (Sasa) comb. n., P. kisotriangulata Sasa etKondo and P. tokaraneoa Sasa et Suzuki, are redescribed as male imagines, and P. togadistalis Sasa, Watanabe et Arakawa as male and female imago. The description of P. littoralis (Tokunaga) is reiterated. A key to male imagines of the known Japanese species of Pseudosmittia is presented.