Terpolymer resins, synthesized by the condensation of salicylic acid and melamine with formaldehyde in the presence of an acid catalyst, proved to be a selective chelating ion-exchange polymer for certain metals. The chelating ion-exchange properties of this polymer were studied for Cu 2 + , Ni 2 + , Co 2 + , Zn 2 + , Fe 3 + , Cd 2 + and Pb 2 + ions. A batch equilibrium method was employed in the study of the selectivity of metal ion uptake involving the measurements of the distribution of a given metal ion between the polymer sample and a solution containing the metal ion. The study was carried out over a wide pH range and in media of various ionic strengths. The terpolymer showed a higher selectivity for Fe 3 + , Cu 2 + and Ni 2 + ions than for Co 2 + , Zn 2 + , Cd 2 + and Pb 2 + ions.