Groundwater remediation by nanoparticles has become a major interest in recent years. This report presents the ability of hexavalent chromium removal in aqueous using iron (Fe0) nanoparticles. Cr(VI) is a major pollution of groundwater and more toxic than Cr(III). Fe0 reduces Cr(VI), transforming Cr(VI) to nontoxic Cr(III). At a dose of iron (Feo) nanoparticles, 100% of Cr(VI) 5mg/l was removed after only 20 minutes. The Cr(VI) removal efficiency increased with decreasing initial pH.