Aim. The purpose was to identify collection accessions – sources of valuable traits to use as starting material for creating varieties of perennial grasses in Western Ukraine. Results and Discussion. Perennial grasses play an essential role in improving the efficiency of forage production. They produce a fodder mass that contains major macro- and micronutrients, minerals, vitamins, amino acids, and other nutrients in available forms, with a high energy protein saturation. Practice shows that due to the introduction of varietal crops into production in combination with optimal technologies of their cultivation, which allows revealing the potential of each variety, it is possible to additionally obtain 20-30% higher yields of fodder mass annually and harvest 2 to 3-fold seed yields. In 2016-2020, a search was carried out and 570 new accessions of perennial grasses were recruited, of which 201 were legumes and 369 were graminaceous grasses. The collection contains 1,319 accessions, of which 232 are Trifolium pratense L., 115 are Trifolium repens L., 49 are Trifolium hybridum L., 107 are Lotus corniculatus L., 80 belong to other legume species (Medicago, Galega orientalis L. Galega orientalis L. and Trifolium species), 131 are Phleum pratense L., 187 are Dactylis glomerata L., 146 are Lolium perenne L., 53 are Arrhenatherum elatius (L.) J. et C.Presl., 67 are Festuca rubra L., 28 are Festuca trachyphylla L., 32 are Bromopsis inermis (Leyss.) Holub, 92 belong to other species of other types of graminaceous grasses (Festuca pratensis Huds., Festuca arundinacea Schreb., Agrostis alba L. etc.). Accessions that enter the Department are registered and sown for propagation in the field. After examination, valuable accessions are transferred to the National Depository and registered in the National Catalogue; the rest of the obtained seeds are used in working collections. Conclusions. The best collection accessions were identified by a set of economically valuable traits: sources of daily growth of shoots (30), winter hardiness (28), plant height (22), yield of green mass upon haymaking (28) and pasture (19) use, forage productivity (15), seed productivity (25), foliage (21), and disease resistance (23). They can be recommended as starting material to create varieties of perennial grasses with high yields of forage mass and seeds for various applications.