The aim of the study was to optimize fermentation parameters for coproduction of protease and cellulase from Bacillus subtilis M-11 in solid state fermentation by a statistical approach and to evaluate the stability and compatibility of enzymes for detergent formulation. Eight different substrates were investigated to find the best medium supporting maximum enzyme productions. Box-Behnken design (BBD) was employed to optimize culture conditions for the coproduction of proteases and cellulose. The effect of pH and temperature, surfactants and commercial detergents on stability of the enzymes was evaluated. Oat flour was found to be the best substrate for production of both enzymes. The results indicate that BBD is an effective tool for optimizing the medium for coproduction of enzymes and the fermentation parameters that affect production of the enzymes. Furthermore, the enzymes showed excellent compatibility with detergents, as well as high stability in wide ranges of temperature (25-60 degrees C) and pH (7.0-9.5). In conclusion, the present study offers a cost-effective method to coproduce protease and cellulase from B. subtilis M-11. Also, it can be suggested that both the enzymes have strong potential for usage in the detergent industry.