This experiment was conducted to determine the effect of fertilizer application on the yield and feeding value of the Korean wild grasses through April to December, 1969. The results obtained were as follows: 1. The heading stage of the various warm season grasses ranged from late July to mid September for the first year after sowing. However, Silsaepul(Calamagrostis arundinacea) and Gaueksae(Eulia apecicsa) did did not head. 2. The plant height was heigher as the fertilizer application was increased. Through a cutting period, the plant height ranged from 50 ㎝ to 90 ㎝ and the hay percentage of the grasses at each cutting stage varied from 22% to 25%, exclusive of Barengi (Digitaria sanguinalis). 3. The significantly more grass yields were observed in the fertilizer application plots than in the non-fertilizer application plot. The grass yield at the first cutting was increased significantly due to the fertilizer application. The effect of fertilizer application on the grass yield was decreased at the successive cutting. In total grass yield, each species showed the following order of high yield to low: Barengi (Digitaria sanguinalis), Sae (Arundinella hirta), Gueryong (Eargrostr`s ferrugines), Sugueryong (Pennisetum japonica), Nadogirumsae (Andropogen micranthus), and orchard grass. 4. In the chemical composition of the grasses, the contents of crude protein was increased as the level of fertilizer application increased in the fertilizer application plots. 5. Hay production cost of some Korean Wild grasses such as Gueryong (Eragrostis ferruginea): 6.80 Won, Barengi (Digitaria sanguinalis): 7.00 Won, Sae (Arundinella hirta): 7.40 Won, Sugueryong (Eragrostis ferruginea) : 9.00 Won, Nadogirumsae (Andropogon micranthus) : 9.50 Won was found far lower than that of orchard grass: 13.00 Won.