The 41 species of two genera: Melanagromyza Hendel (17 species) and Ophiomyia Bražnikov (24 species) in Japan have been revised: eleven species are endemic; four new species, Melanagromyza brevivillosa n. sp., Ophiomyia corrugata n. sp., O. filifera n. sp. and O. turgida n. sp. are described; two species, Ophiomyia paramaura Pakalniškis, known from Lithuania, and O. placida (Spencer), known from Australia, are recorded for the first time; Melanagromyza boninensis Spencer is transferred to Ophiomyia and Ophiomyia crepidula Sasakawa to Melanagromyza; Melanagromyza variegata Spencer is synonymized with M. pubescens and M. oligophaga Spencer with M. dettmeri, and Ophiomyia krousianica Černý with O. paramaura Pakalniškis.