The electrochemical and electrogenerated chemiluminescence (ECL) properties of gold and indium tin oxide (ITO) electrodes modified by a tris(2,2’-bipyridine)ruthenium(II) (Ru(bpy)(3)(2+)) derivative with two tridecanethiol groups were studied. Although the electrochemical response of the gold electrode modified by the Ru(bpy)(3)(2+)-tridecanethiol derivative was irreversible and unstable because oxidation of the gold surface and the thiolate monolayer itself started before oxidation of the Ru(bpy)(3)(2+) head group, the modified ITO electrode showed the stable redox of Ru(bpy)(3)(2+) head group. Both the modified gold and modified ITO electrodes showed ECL properties in solution containing C2O42-. We also found that a monolayer of the Ru(bpy)(3)(2+) -tridecanethiol derivative on ITO acts as a mediator for the oxidation of C2O42- in solution. Transient responses of current and ECL intensity of ITO and gold electrodes modified with the Ru(bpy)(3)(2+)-tridecanethiol derivative were also studied to elucidate the ECL mechanism.