Subfamily Ismarinae traditionally has been belong to the superfamily Proctotrupoidea, family Diapriidae. But recently, Sharkey (2007) has been placed family diapriidae in a separate superfamily of the infraorder Proctrupomorpha, the Diaprioidea, together with the New Zealand endemic Maamingidae and the cosmopolitan and speciose Diapriidae. After, subfamily Ismarinae is raised to family status Ismaridae stat. nov., also included the family Ismaridae within Diaprioidea (sharkey et al. 2011). The superfamily Diaprioidea Haliday, 1833 is a moderate large group of parasitoid wasps. Diaprioidea comprise five families (four extant family: Diapriidae Haliday 1833, Ismaridae Thomson 1858, Maamingidae Early, Masner, Naumann & Austin 2001 and Monomachidae Ashmead 1902; one fossile family Spathiopterygidae Engel & Ortega-Blanco 2013) of generally fairly small wasps, with a total of 2,109 species in the world. Family Ismaridae is a small family contains a single genus and 32 described species in the world and previously unrecorded in Korea. Ismaridae is morphologically distinguished from other families of Diaprioidea by the following combination of characteristics: antennae inserted close to the clypeus; position of toruli that are opening forward (not upward); notauli absent, with mesocutum broadly arched in lateral view; antennal formula 15-14. Also, the biology of this family is very poorly studied, only a few species known as hyperparasitoids of Auchenorrhyncha (Hemiptera) through dryinids (Hymenoptera). In this study, A new species, Ismarussp. nov. and one unrecorded species, Ismarus halidayi Foerster 1850, are reported from South Korea. Photographs of diagnostic characters are provided herein.