Abstract: Subject polymers have a plurality of repeating units having amino-bis-phosphonate functionality pendent groups of a polyacrylate, polymethacrylate, polyacrylamide, polymethacrylamide, or linear polyethyleneimine. The polymers are prepared from a plurality of monomers comprising amino-te-phosphonate functionality or from a polymer having NHBoc or active ester pendent groups that are subsequently transformed into the amino-bis-phosphonate comprising polymer. The amino-bis-phosphonate comprising polymers or their precursor polymers can be prepared by RAFT polymerization or by transformation of a preformed polymer. The amino-bis-phosphonate comprising polymers can be linear or branched polymers. The amino-bis-phosphonate comprising polymers can be complexed with metal ions. The metal ions can be a radionuclide and the amino-bis-phosphonate comprising polymer complexes can be used as radiotherapeutic agents.