Two novel triterpene holostane nonsulfated pentaosides, kolgaosides A (1) and B (2), and one known, holothurinoside B (3), were isolated from the Arctic sea cucumber Kolga hyalina, the second representative of the family Elpidiidae, order Elasipodida, from which triterpene glycosides have been obtained. The structures of 1 and 2 were elucidated using 1H and 13C NMR and 2D NMR procedures (HSQC, HMBC, COSY, ROESY, TOCSY) and HRESI mass-spectrometry. Kolgaosides A (1) and B (2) demonstrate low cytotoxic activity against the cells of the ascite form of mouse Ehrlich carcinoma and moderate hemolytic activity against mouse erythrocytes, despite the presence of hydroxy groups in the side chains of the aglycones. The glycosides of K. hyalina are similar to those of the Antarctic sea cucumber Rhipidothuria racowitzai Hèrouard, 1901 (=Achlionice violaescupidata) (Elasipodida: Elpidiidae); this may have chemotaxonomic significance.