Cleaning and removal of water hyacinth from lakes and various historical places government spends lacks of rupees per year. High rate of propagation and easy availability, water-hyacinth could be used as a renewable carbon source for alcohol (fuel ethanol) production. Water-hyacinth’s (Eichhornia crassipes) hemicellulose acid hydrolysate has been utilized as a substrate for alcohol production using Pichia stipitis NCIM3497. Acid hydrolysis were carried out by using (1% v/v) sulfuric acid. Perhydrolysate was detoxified, boiled and overlimed up to pH 10.0 with NaOH to produce acid hydrolysate. Acid hydrolysate had higher fermentability than perhydrolysate. Freshly prepared acid hydrolysate was directly used in fermentation broth as substrate. Fermentation was carried out for 40 hrs. Total reducing sugars were 51.3 gm/lit and at the end of 40 hrs the fermentation it was 9.2 gm/l. About 82.06% of the available sugars were utilized within 40 hrs. At the end of fermentation, alcohol was estimated by of K2Cr2O7 method, which is 19.2 gm/lit and an alcohol yield of 0.45 gm/gm sugar utilized. Considering the cost various feed stock, use of water- hyacinth which is freely available in large amount as a substrate, offers an opportunity to reduce the cost of fuel alcohol production.