Sepiolite-based molybdenum catalyst (Sep-Am-MoO2) was prepared by immobilization of a bis-acetylacetonatodioxo-molybdenum (VI) complex [MoO2 (acac)(2)] onto the surface of sepiolite clay mineral which was functionalized by 3-(tri-methoxysilyl)propylamine (MSPA). Then the surface-functionalized sepiolite was characterized by the Fourier transform-infrared (FT-IR), X-ray fluorescence and X-ray-photoelectron spectroscopies along with powder X-ray diffraction, thermal analysis, elemental analysis, inductively coupled plasma (ICP), and surface area (BET) techniques. Then it was applied for the catalytic epoxidation of cis-cyclooctene and the effect of several parameters such as the solvent, catalyst and oxidant contents, temperature, and time on this reaction were studied. Then it was used for the epoxidation of some other alkenes. Furthermore, because the use of this novel catalyst in large-scale reactions showed great catalytic activity, it could be a convincing candidate for the application in industry. More importantly, natural and cheap clay mineral precursor, facile preparation, simple work-up procedure, high product yield, high turn-over frequency, (TOF), and easy recovery and reusability, make Sep-Am-MoO2 an efficient candidate as a catalyst for the epoxidation of alkenes in the research and industrial applications.