Organically bound sulfur is a common impurity in carbon blacks, such as vulcanized carbon and coal. Whereas this organosulfur is usually removed by heating to high temperatures, we describe a low-temperature method to desulfurize solid carbon via oxidation (ultimately to SO4 2-) on a Pt catalyst in oxygenated aqueous media. The reaction is monitored on Vulcan carbon, which is the favored support for the Pt catalysts used in fuel-cell electrodes but which has a high concentration (nominally 5000 ppm) of organosulfur. Vulcan carbon is electrodesulfurized by dispersing it in a heated, dilute HNO3 electrolyte where it can physically contact a Pt mesh anode that is maintained as Pt oxide. After 40−180 min of electrolysis in oxygenated solution at +1.0 V versus Pd/H, sulfate is present in the electrolyte (as measured by precipitation of BaSO4). X-ray photoelectron spectroscopy of the dried, electrodesulfurized carbon shows that ∼30% of the near-surface organosulfur is removed. The remaining sulfur presumably does not react because it does not physically contact the hydrous platinum oxide (PtO x H y ) at the electrode surface. Minimal desulfurization occurs at 0.2 V versus Pd/H, when the Pt mesh surface is composed of Pt0. These electrochemical results show that oxidized Pt is the catalyst necessary for oxidative desulfurization. In deoxygenated solution, electrodesulfurization still occurs for electrolyses at +1.0 V versus Pd/H, but SO4 2- is not generated, indicating that SO2 is the partial oxidation product. The surface area and total oxygen content of the carbon are unaffected by the electrodesulfurization process. This simple, low-temperature method for desulfurization should be applicable to other forms of solid carbon containing organosulfur moieties.