Catalysts consisting of molybdenum incorporated into MCM-41 mesoporous molecular sieves (MoMCM-41) were synthesized and characterized by XRD, N-2 adsorption/desorption, ESR, FTIR, and UV-vis analysis techniques. The MoMCM-41 catalysts were synthesized by addition of Na2MoO4. 2H(2)O as molybdenum source at the initial step of synthesis; the framework Mo in MoMCM-41 catalysts could be confirmed by ESR, FTIR and UV-vis. As the molybdenum content is increased, the structure of MoMCM-41 changed from hexagonal to amorphous. Molybdenum loading up to ca. 10% was a maximum concentration that was obtained in this study. The MoMCM-41 catalysts showed a catalytic activity for propylene oxidation.