The metal-ion uptake behavior of the chelating resin poly([(3-(methacryloylamino)propyl] trimethyl ammonium chloride-co-4-vinyl pyridine) has been investigated. The resin is obtained by radical copolymerization in a yield of 99.6%. The hydrophilic resin shows a high retention capacity and selectivity toward Hg(II) ions in the presence of Cu(II), Pb(II), Cd(H), Zn(II), and Cr(III) ions. A retention of Hg(II) higher than 99% is observed after 5 min.