The effect of four nitrogen sources on the enzymatic activity of alkaline proteases from a wild strain of Alkalophilic Bacillus sp cultivated to different concentrations from CSL (Corn Steep Liquor). was evaluated. The growth of the strain is not affected by pH of inoculation of 7,0, 8,5 and 9,5, in contrast to the enzymatic activity and true protein production, that had their better results to initial pH of 8,5. To this initial pH of 8,5; two organic nitrogen