The complexing properties of Diphonix, a new chelating ion-exchange resin, toward indium and gallium cations was investigated. Variables included bead size, contact time, solution pH, and the presence of competing cations. The resin, which contains diphosphonic acid ligands, displayed rapid rates of complexation and high selectivity under acidic conditions. Metal uptake from 1 M sulfuric acid solution under continuous flow conditions was 0.47 mmol/g (33.0 mg/g) for gallium and 0.76 mmol/g (87.8 mg/g) for indium. The resin may be regenerated by elution with 1-hydroxyethane-1, 1-diphosphonic acid or hydrochloric acid.