In this study, electrochemical behaviour of selenite was investigated in the presence of Pb(II) in acidic media,. using cyclic voltammetry. In selenite solution, there are two cathodic peaks at -0.54 and -0.59 V and one anodic peak at -0.52 V. When both selenite and Pb(II) are present in the same solution, three new peaks appeared at -0.25, -0.30 and -0.82 V in cathodic scan and two new peak at -0.12 and -0.21 V in the anodic scan beside peaks of selenite and Pb(II). These anodic peaks were attributed to the oxidation of lead in Hg(SePb) and SePb(on Hgs) to Pb(II) and elemental mercury to Hg(II). The peaks at -0.25 and -0.30 V were attributed to the reduction of Pb(II) on the HgSe and the reduction of Pb(II) on the Se-(on HgSe), respectively. The peak which appeared after the reduction peak of selenite at -0.82 V was taken as the decomposition of Hg(SePb) and SePb(on HgSe) films to H2Se.