Bromide oxidation and bromine reduction in propylene carbonate (PC) +1 M LiClO 4 was investigated voltammetrically using polycrystalline platinum rotating disc electrode. The corresponding voltammograms were compared to those of iodide oxidation and HCl decomposition. The oxidation 2Br - ->Br 2 +2e - was found to proceed through two steps, which are caused by the formation of a stable intermediate Br 3 - ion. The stability constant of tri-bromine ion was estimated to be 10 5 . 5 M. The diffusion coefficient of Br - ion in this solution was determined to be 3.41x10 - 6 cm 2 s - 1 . In the case of bromine reduction, a time dependence of the shape of the voltammogram was observed, which showed that one is dealing with a direct bromination of PC.