The cross-linked polyzwitterion/anion for the removal of strontium from aqueous solutions is a polyzwitterion having the following structure: and the corresponding anion formed by treating the polyzwitterion with a base, e.g., sodium hydroxide. The cross-linked polyzwitterion/anion (CPZA) was prepared using Butler's cyclopolymerization protocol. The CPZA resin was found to have a very good adsorption capacity for Sr2+ ions at low concentrations. The relatively strong rapid initial adsorption of 83% Sr2+ ions was followed by slower adsorption of the remaining 17%, which was described by an intraparticle diffusion model. The adsorption followed the Lagergren second-order kinetic model, and Temkin as well as Freundlich isotherm models. The negative ΔGs and ΔH ensured the spontaneity and the exothermic nature of the adsorption process. The excellent adsorption and desorption efficiencies implied the efficacy of the resin in removing (as well as recovering) the metal ions from aqueous solution.