As a result of examining the specimens collected from various freshwater bodies since 1995, four eutardigrades are added to Korean fauna: lsohypsibius brevitubulatus n. sp., I. baldii (Ramazzotti), I. marcellinoi (Binda and Pilato), and Diphascon (Diphascon) higginsi Binda. I. brevitubulatus n. sp. differs from its congeners by having a combination of the following characteristics: smooth cuticle, rather big body size, short and broad buccal tube, presence of lunules, and pharynx bearing 3 rod-like macroplacoids without microplacoid. All the species are illustrated and briefly commented on their habitats with the associated fauna.