A new chelating polymeric sorbent has been developed using impregnation of Amberlite XAD-7 resin with a newly-synthesized hexadentates naphthol-derivative Schiff base 1-[(1E, 9E)-10-(2-hydroxy-1-naphthyl)-4,7-dioxa-2,9-diaza-1,9-decadienyl]-2-naph th(EHND). The impregnated resin showed high binding affinity for Ga(III) and In(III) ions and was used for their preconcentration prior to determination by flame AAS. The optimum pH values for the quantitative sorption of Ga(III) and In(III) are 4.0-6.0 and 4.5-8.0, respectively, and their desorptions can be achieved by using 5mL of 1M HNO3. The sorption capacities of the resin for gallium and indium were 1.1 and 1.3mg g(-1), respectively. The enrichment factor for preconcentration of gallium and indium was found to be 200. The precision of the method, evaluated as the relative standard deviation obtained by analyzing a series of ten replicates, was below 2.5% for both elements. The practical applicability of the polymer was tested with synthetic seawater, natural waters, wastewater and human blood serum.