Glutathione (GSH; gamma-glutamylcysteinylglycine) is ubiquitous in mammalian and other living cells. It contains an unusual peptide linkage between the amine group of cysteine and the carboxyl group of the glutamate side chain. It has several important functions, including protection against oxidative stress. It is synthesized from its constituent amino acids by the consecutive actions of gamma-glutamylcysteine synthetase and GSH synthetase. Cellular levels of GSH may be increased by supplying substrates and GSH delivery compounds. Increasing cellular GSH may be therapeutically useful. In this study, we investigated the applicability of the glassy carbon electrode coated with thin Hg film layer to the determination of reduced glutathione (GSH). For this purpose, firstly, Hg coating process parameters were studied such as concentration of mercury coating solution, coating current, coating temperature. Then, working conditions were investigated. At the end of these studies, we concluded that although some of limitations, the sensor would be applicable to the determination of reduced glutathione.