This study aimed to evaluate effects of replacement of ensilaged water hyacinth (Eichhornia crassipes) to Para grass (Brachiaria mutica) in the diets (DM basis) on feed intake, rumen parameters, nutrient digestibility and nitrogen retention of growing sheep. Four growing sheep (19.8±0.43kg) were allocated in a 4x4 Latin square design with 4 treatments including Para grass (EWH0), replacement of 15% Para grass by ensilaged water hyacinth (EWH15), replacement of 30% Para grass by ensilaged water hyacinth (EWH30), replacement of 45%Para grass by ensilaged water hyacinth (EWH45). There was a supplementation of coconut meal, soybean cake and urea to adjust the CP content of diets being 17%. Each experimental period was 14 days including 7 days for adaptation and 7 days for sample collecting. The conclusion was that EWH could be used to feed growing sheep without adverse effects on rumen parameters, and the replacement level of 30% EWH toPara grass in diet gave a better result.