[en] Uranyl fluoride and other uranium salts have been found to form complexes with the macrocyclic polyethers 1, 4, 7, 10, 13, 16-hexaoxacyclooctadecane (18-crown-6), 2, 5, 8, 15, 18, 21-hexaoxatricyclo [20.4.0.0⁹'¹⁴] hexacosane (dicyclohexyl-18-crown-6) and 1, 4, 7, 10, 13-pentaoxyacyclopentadecane (15-crown-5). These complexes are synthesized either by direct combination of the reactants at 80⁰ or from solution in a suitable solvent. Some complexes display various hydrated forms whose production is dependent on the synthetic route and reaction conditions. Characterization is accomplished by several methods and thermal, elemental, and spectrophotometric analyses present unusual problems with regard to stoichiometry, association, and secondary reactions. The solution behavior of the complexes is discussed and efforts to recover the uranium from the complexes are described