Lead ion adsorption on the surfaces of pristine and oxidized graphite is studied quantitatively using X-ray photoelectron spectroscopy (XPS) and standard electrochemical measurements. The XPS analysis confirmed the oxidation of graphite, yielding a final composite consisting of 15.97% of oxygen and 84.03% of carbon in comparison with the pristine graphite powder consisting of 6.13% oxygen and 93.87% carbon. The adsorption of lead (II) ion was confirmed by the peaks observed at 138 eV and 143.8 eV, associated with the emissions from Pb4f 7/2 and Pb4f 5/2, respectively. The effective concentration of Pb2+ ion and the optimum dosage of oxidized graphite were calculated to be 400 µM and 200 mg, respectively. Adsorption capacity of bare graphite was 41.18%, whereas that of oxidized graphite was 73.3%. The present results show that graphite oxide is a candidate material for the adsorption of Pb2+ ion from water.