The nutrient profile, phytochemical composition, and silage quality of water hyacinth (WH) were determined and compared to Napier grass (NG), a common forage in ruminant diets. Ensiling improved the nutrient profile of WH and NG because of the significantly higher (P<0.05) dry matter (DM) and crude protein (CP) and significantly lower (P<0.05) neutral detergent fiber (NDF) and moisture content (MC) of ensiled WH (EWH) and ensiled NG (ENG). Ether extract (EE) values were not significantly different (P>0.05). Qualitative phytochemical analyses indicated the presence of flavonoids and cardiac glycosides in WH, NG, EWH, and ENG. Tannins were present only in WH and NG however only ENG and NG contained saponins. Ensiled WH had pH values of 3.61 to 3.91 and lactic acid concentrations of 94.33 to 125.48 g/kg DM indicating good silage quality. Furthermore, EWH had better CP (11.07%) and NDF (47.37%) than WH (9.23% CP, 55.26% NDF), NG (6.21% CP, 71.02% NDF) and ENG (7.95% CP, 58.73% NDF) which most likely will favor better ruminal fermentation in ruminants. Therefore, based on these properties, EWH has the best potential as a substitute for NG in the Philippines.