Glutathione (GSH) is the most abundant intracellular thiol. This tripeptide, the y-L-glutamyl-Lcysteinylglycine, is present inside cells as free sulfhydryl (reduced-form GSH) and in the oxidized-form GSSG, which is converted to GSH by the intracellular enzyme glutathione reductase, in the presence of NADPH. GSH presents numerous functional activities in intermediate metabolism, biosynthesis of macromolecules, transports, cancer therapy, and radioprotection. In all its multifunctional roles, GSH is in the globally monoanionic form GSH-and the three charged groups (the positive amino group and the two negative carboxylate groups) are strongly involved with regard to the environment, particularly, in the GSH-enzyme interactions. Therefore, the intrinsic electrostatic properties of GSH are the first step to the understanding of the molecular mechanism ofthese interactions. In our study, we present electrostatic properties of GSH, versus various allowed conformations, using ab inifio computations. Charges distributions and molecular electrostatic potentials are discussed with regard to the involvement of GSH in its various functions.