Abstract: Optimum incubation period, temperature and pH for production of extracellular alkaline protease production by novel bacterium Halobacterium sp. AF1 were investigated. The protease were also characterized for its stability on various environmental conditions. Extracellular thermo-alkaline activity was determined by measuring proteolytic activity of the culture supernatants and stability of the protease was determined by incubating protease under different environmental conditions. The optimum production of AF1 protease was achieved within 72 h of culture at 40°C with the pH 8. The activity of the protease produced by this organism was stable up to 91% at 70°C and 83% at pH 9.5. AF1 protease was not only stable in the presence of organic solvent (25% v/v) but also exhibit a higher activity for acetone and n-hexane than in the absence of solvents. These results suggested that the protease produced by the organism was thermo-stable organic solvent tolerant extracellular alkaline protease. The remarkable stability was found for 5 mM Ca+2, Na+, Hg+2 and Fe+3 as they had been showed marginal effect on proteolytic activity of isolated protease. The AF1 protease was retained their activity up to 57-67% for 1.5% sodium dodecyl sulfate and H2O2. Higher proteolytic activity was found for gelatin (1% w/v) than that of casein or bovine serum albumin. The AF1 protease exhibited excellent stability towards temperature, pH, organic solvents and metal ions. These properties make it suitable to be used in tannery industrial applications as well as detergent additive which reduce the industrial use of chemicals wastes in the environment.