Nitrate ((NO - 3 ) contamination of groundwater is a major concern throughout intensive agricultural areas (nonpoint source pollution). Current processes (e.g., ion exchange, membrane separation) are not selective for NO - 3 removal. The objective of this study was to develop a catalytic reduction process to selectively remove NO - 3 from groundwater associated with agricultural community. Three catalysts, palladium (Pd), platinum (Pt), and rhodium (Rh) on carbon (5-10%) were tested in this study. A l of groundwater sample was amended with 0.5<space>g catalyst and reacted at different redox potentials (340 to -400<space>mV) and reaction times (1-6<space>h). During the catalytic reduction process the pH was maintained around 6.5 by bubbling 5% carbon dioxide (CO 2 ). At a given redox potential and reaction period, samples were analyzed for NO - 3 and NO - 2 (nitrite) with ion chromatography (IC). Initial NO - 3 concentrations ranged between 32 and 41<space>mg/l. Among the three catalysts, Rh was most effective in removing NO - 3 . Results suggest that Rh catalyst at -400<space>mV and 6<space>h reaction time can decrease NO - 3 concentration from 40 to 11.9<space>mg/l. During the NO - 3 reduction process NO - 2 was not detected. The re-oxidation of formerly reduced samples to 390<space>mV resulted in no increase in the concentration of NO - 3 . Application of a small flow of current to the catalytic reduction process increased NO - 3 reduction rates significantly. For instance, application of 4.6-6.1 ν to -250<space>mV and 6<space>h of reaction time decreased NO - 3 concentration from 40 to 7.9<space>mg/l. The catalytic reduction process described in this study is useful in removing NO - 3 from groundwater associated with nonpoint source pollution.