Two euphorine taxa from the tribe Cosmophorini, the genus Cryptoxilos Viereck, 1911 and the subgenus Eucosmophorus Belokobylskij, 2000 (genus Cosmophorus Ratzeburg, 1848) are recorded for the first time for the Korean Peninsula. Three species from South Korea, Cosmophorus (Eucosmophorus) jejuensissp. nov., C. (Eu.) wandoensissp. nov., and Cryptoxilos (Cryptoxiloides) ulleungussp. nov., are described and illustrated. Keys to the described species of Cosmophorus (Eucosmophorus) and Cryptoxilos (Cryptoxiloides) are provided. Digital photographs of the type species of the subgenus Eucosmophorus, Cosmophorus undulatus Belokobylskij, 2000, are published for the first time.