The primary amine -CH2NH2 ligand bound to cross-linked polystyrene has a high affinity for the uranyl ion from a matrix of artificial seawater. The uranyl capacity is 14.8 mg U/g(polymer), compared to 2.34 mg U/g(polymer) for a diamidoxime ligand on a polystyrene support. Secondary and tertiary amines have much lower affinities, indicating that steric effects are important to the complexation. The results with polystyrene-bound -CH2NH2 thus suggest at least a 3-fold increase in uranyl capacity (calculated on a per mole ligand basis (not per gram of polymer, in order to make the results independent of the weight of the polymer support)) and a 4-fold increase when ligands with two primary amines per ligand are utilized. An additional advantage of the primary amine over amidoxime is that it is a simpler ligand to prepare.