Proteases from viscera of Silver carp (Hypophthalmichthys molitrix) fish have been extracted and characterized. The alkaline proteases show optimum activity in 0.2M Tris-HCl buffer at pH 8.5 and 45°C using soluble milk casein as substrate. The crude alkaline protease lost about 35% or 51% of its specific activity if it was heated at 50C or kept at pH 9 for 60 min., respectively. Purification of proteases purified by ammonium sulfate precipitation, gel-filtration using Sephadex G 50 column and ultrafiltration via polyamide membrane (30 KDa) led to increase its specific activity up to 20, 24 and 99 fold, respectively.