In this work bovine albumin was used innovatively as a medium for adsorptive accumulation of Se-I-2 on thin mercury film electrode. Se-I-2 was formed by reaction between Se(IV) and iodide in HCl media. The adsorbed Se-I-2 was stripped in 0.05 M HCl by differential pulse cathodic potential scan. The proposed method was successfully applied to analysis of Se(IV) and Se(VI) in natural waters sampled from some lagoons south of Caspian Sea. The optimum reaction conditions and other analytical parameters and influence of cations and anions were studied. The detection limit was 0.37 ng mL(-1). The obtained results were compared with the results of DPCSV after electrochemical preconcentration, HG-AAS and ICP-AES. (C) 2009 Elsevier B.V. All rights reserved.