High surface area, ordered mesoporous SBA-15 and Al-SBA-15 were synthesized using published procedures and used as support for Mo and W catalysts promoted with Co and Ni. The molybdenum loading was varied on Al-SBA-15 from 2 to 12 wt %, and Co or Ni loading was varied on 8%Mo/Al-SBA-15 from 1 to 5 wt %. The support and catalysts were characterized by X-ray diffraction (XRD), Barett-Joyner-Halenda (BJH) pore-size distribution, Brunauer-Emmett-Teller (BET) surface area, Fourier transform infrared (FT-IR), temperature-programmed reduction (TPR), and oxygen chemisorption. The characterization results indicated that hexagonal mesoporous structure is retained on Mo, CoMo, and NiMo catalysts. The TPR studies indicated that there are significant differences in Mo reducibilities and reducible species that are present on SBA-15 and Al-SBA-15 supported catalysts. The catalytic activities for thiophene, hydrodesulfurization (HDS), and cyclohexene hydrogenation (HYD) were carried out as a function of Mo and CoMo or NiMo loadings at 400 degrees C on sulfided catalysts. The results indicated that the molybdenum is dispersed well up to 8% Mo loading and 8 wt % loading is optimum for catalytic activities. Oxygen chemisorption correlated well with catalytic activity. The reducibilities of the catalysts and their relation to catalytic activities are discussed. A comparison of the physicochemical properties and catalytic activities of Mo and W catalysts supported on SBA-15 and Al-SBA-15 is made.