We have identified a polydentate aminocarboxylate ligand that stabilizes uranyl(V) in water. The mononuclear [UO2(dpaea)]X, (dpaeaH(2) = Bis(pyridyl-6-methyl-2-carboxylate)-ethylamine; X = CoCp2*(+) or X = K(2.2.2.cryptand) complexes have been isolated from anaerobic organic solution, crystallographically and spectroscopically characterized both in water and organic solution. These complexes disproportionate at pH <= 6, but are stable in anaerobic water at pH 7-10 for several days.