A polystyrene divinylbenzene resin (Amberlite XAD-16) functionalized by 1-(2-pyridylazo) 2-naphtol has been synthesized and its sorption properties have been investigated for preconcentration of Ni(II), Cd(II), Co(II), Cu(II), Pb(II) and Cr(III) in natural water samples. The new resin (XAD-16-PAN) was characterized by thermogravimetric analysis and infrared spectrometry. The analytical parameters including pH, sample volume etc. for the quantitative recoveries of the analyte ions using XAD-16-PAN resin were investigated. The effects of alkaline, earth alkaline ions and some anions on the sorption of analyte ions were also examined. The recovery values were greater than 95% and the preconcentration factor was 200 for all analyte ions. The relative standard deviations of the determinations by flame atomic absorption spectrometry were less than 8%. The detection limits of the analyte ions (k=3, N=21) were varying from 0.056 mug/L for Cd to 0.268 mug/L for Cr.