Surface-modified alumina has been developed as a column material of (n,g) and (n,f) 99Mo/99mTc generators. Technitium-99m (99mTc, t1/2 = 6hr) is one of the most widely used diagnostic radioisotopes. This radionuclide is normally extracted from a lead-shielded column on which either (n, g) or (n,f) 99Mo is adsorbed. By utilizing the differences of the chemical properties of these two isotopes, 99mTc can be eluted regularly from the loaded columns for everyday uses. (n,g) 99Mo can easily be obtained by a neutron irradiation from a research reactor. However, (n,g) 99Mo contains mostly non-radioactive natural molybdenum. Hence, a high capacity material, which adsorbs molybdenum several times more than the adsorbents for (n,f) 99Mo/99mTc generators is required. The developed material from this study has approximately 217 mg/g of the uptake capacity. In addition, the molybdenum loading process is as easy as a (n,f) 99Mo loading process. Hence, this material is useful enough for the production of (n,g) 99Mo/99mTc generator columns.