Chelating polymers containing an alpha-aminobenzylphosphonic acid group or an alpha-aminopyridylphosphonic acid group have been prepared starting with a crosslinked polyaminomethylstyrene. Chemical modification was achieved via the addition of diethyl phosphonate followed by hydrolysis (Kabachnick-Fields reaction) or by the addition of phosphorous acid onto the corresponding polyimines. Preliminary evaluation of the sorption capacities towards Ca2+ and Co2+ have shown that the prepared polymers exhibit similar or slightly greater chelating properties than a commercial resin (Duolite ES 467). It was also found that polymers containing an alpha-aminopyridylphosphonic acid group displayed a significant affinity towards Co2+, contrary to resins containing an alpha-aminobenzylphosphonic acid group.