This study aimed to assess the effect of the aging period on the efficiency of nanoscale zero valent iron (nZVI) for nitrate removal from water. A series of batch tests to evaluate changing in the efficiency of nZVI for nitrate removal over a range of aging time (0-90 days) under different storing conditions such as temperature, air condition, and solvent has been investigated. The effect of temperature ranged from 5℃ to 20℃, the air condition of atmospheric air and nitrogen gas, the solvent in water, 50% volume ratio of ethanol and ethanol was studied. Scanning electron microscopy (SEM) was used to investigate the changes in the physicochemical properties of again nZVI. The results proved that lower temperature, atmospheric air, and ethanol were the best storage conditions to keep the high efficiency of aging nZVI.