Several nitrogen-containing compounds, such as nitrate, have been found as common pollutants in drinking water. Nitrate can cause several environmental problems. Excessive amount of nitrate in water can stimulate eutrophication which is the term refers to abundance of aquatic plants, growth of algae, and depletion of dissolved oxygen. Furthermore, the presence of nitrate ions in drinking water is a potential public health hazard, including infant methaemoglobinaemia. Among current techniques for nitrate removal, adsorption methods are promising, because they allow simple and economical operation, resulting in less sludge production and disposal problems. On the other hand, during the last two decades, the so-called mesostructured materials such as SBA-15, have received much attention due to their specific features like enormous surface area. So, the present wok is intended to study the adsorption of nitrate from aqueous solutions using modified SBA-15. At first, SBA-15 was prepared and calcinated according to the synthesis strategy which has been introduced by Zhao and co-workers. Characterization techniques such as X-Ray Diffraction and Adsorption/Desorption Nitrogen were used to investigate physicochemical characteristics of SBA-15. X-Ray Diffraction (XRD) patterns of prepared samples confirm the structure of the mesoporous materials. The S BET and V Total which were calculated using BJH and BET formula were respectively 659.14m 2 /g and 0.88cm 3 /g. In order to modify the synthesized structures, SBA-15 was introduced to solutions containing different amounts of Lanthanum precursor, so different La/SBA-15 mass ratios were prepared. Initial experiments showed that nitrate removal was not effective for La x -SBA-15. In the next step adsorption of nitrate anions from aqueous solutions was investigated on ammonium-functionalized SBA-15. This adsorbent was prepared via post synthesis grafting method using aminopropyltriethoxysilane, followed by acidification in HCL solution. The results showed that NH 3 + -SBA-15 had a great nitrate adsorption capacity. X-Ray Diffraction (XRD) patterns of NH 2 -SBA-15 confirm the structure of the mesoporous materials. The S BET and V Total for NH 2 -SBA-15 were respectively 313.49m 2 /g and 0.41cm 3 /g. According to further experiments, equilibrium time were found to be 10 min for nitrate removal by this adsorbent and a good agreement of the experimental data with the second-order kinetic model was observed for NH 3 + -SBA-15. The values for the Langmuir (R 2 = 0.98) and Frendlich isotherm (R 2 = 0.92) constants indicate the adequacy of these isotherms model to explain the adsorption process by NH 3 + -SBA-15.