Commercial denim fabrics-cotton, tencel, cotton/tencel, cotton/rayon, cotton/PP-were treated with cellulase under different concentration, temperature, time and rpm. Weight loss, color difference, tear strength, flexibility of the treated and the untreated samples have been measured and compared. Weight loss decreased in the order of C>C/P, C/R>C/T>T as the concentration of cellulose, treating time, temperature (up to 60 $^{circ}C$), and rpm increased. Tear strength retention decreased in the order of T>C/T>C>C/R>C/P as the concentration of cellulase, treating time, temperature (up to 60 $^{circ}C$), and rpm increased. Color difference and the flexibility of all samples increased as the concentration of cellulase, treating time, temperature (up to 6$0^{circ}C$), and rpm increased.