A method for separation-preconcentration of Cu(II) and Pb(III) ions by membrane filtration has been presented. The analyte ions were collected on acetate membrane filter as their 1-2-pyridylazo 2-naphthol (PAN) complexes. The analytes were determined by flame atomic absorption spectrometry. The analytical parameters including pH, eluent type, sample volume. amount of PAN, etc. were examined in order to gain quantitative recoveries of analyte ions. The effects of foreign ions on the recoveries of analyte ions were also investigated. The detection limits by three sigma were found to be 1.2 and 3.5 mu g L(-1) for Cu(II) and Pb(II). respectively The preconcentration factor was 60 for Cu(II) and 20 for Pb(II). The validation of the presented procedure was checked by the analysis of certified reference materials The optimized method Was Successfully applied to food, water and geological samples with good results (C) 2009 Elsevier Ltd All rights reserved.