To improve the low content of crude protein and low quality fermentation of napiergrass silage, ensiling with phasey, bean was examined. Napiergrasses. (Pennisetum purpureum cv. Merkeron), hybrid napiergrass (Pennisetum purpureumx Pennisetum typhoides) and phasey bean (Macroptilium lathyroides cv. Murray) were cultivated in Fukuoka, Japan. The first growth of napiergrasses and phasey bean were harvested at 90 days of age and chopped into about 1 cm lengths. The mixing levels of phase?; bran with napiergrasses were 0, 25, 50 and 75. 700 g of plant materials were ensiled into a laboratory silo {1.0 litre. polyethylene container) and incubated for 30 days. After opening silos. pH. total nitrogen (TN), volatile basic nitrogen (VBN) and organic acids (lactic acid: I-A. acetic acid: AA, butyric acid: BA) were determined. The experiment was a factorial design of 2x4 with 3 replicates. The data were analyzed statistically by two-way analysis of variance. Without inclusion of phasey bean, lower quality was observed For hybrid silage than for Merkeron silage. The inclusion of phasey bean at the rate of 25% increased DM and TN, and decreased pH value. VBN/TN, AA and BA in both Merkeron and hybrid napiergrass silages. The value of pH, TN. VBN/TN. AA and BA H ere not significantly different among 25. 50 and 75% mixing levels of phasey bean. LA production increased significantly with the increase in phasey bean mixing level in both hybrid and Merkeron silages. At all mixing levels of phasey bean. LA production did not show significant differences between Merkeron and hybrid silages.