The subfamily Acaenitinae Föster, 1869 is a small-sized subfamily belonging to the family Ichneumonidae. Members of Acaenitinae distributes in Ethiopian, Oriental, and Palearctic Regions. Twenty six genera have been recorded in the World, and six genera are known from Korea. The biology of the Acaenitinae is not well known, however, some hosts are recorded from Cerambycidae in Coleoptera (Gardiner, 1960), Sesiidae and Tortricidae in Lepidoptera (Ulbricht, 1909; Starke, 1956). Generally female is easily distinguished from that of other subfamily of Ichneumonidae. They can be recognized by their very elongate subgenital plate, and by the auxiliary tooth on the tarsal claws. Male can be also easily recognized by the form of the claws and the facial shape. In this study, we found a newly recorded genus Yezoceryx, belonging to the Tribe Acaenitini, with two species in Korean fauna. Illustrated key of species and genera, diagnosis and photographs of each species are provieded.