Diesel engine emissions are a source of environmental concern. The use of vegetable oil based fuels, called biodiesels, lowers particulate emissions due to the increased oxygen content of the fuel. This study aims to further increase the oxygen content of biodiesel by oxidizing the fuel, analyzing the resulting product, and determining if favorable lubricity qualities result. Oxidation is performed in a non-catalytic vapor phase reactor at temperatures between 300-400°C. The product is characterized using various analyses including sulfuric acid solubility, density, gas chromatography, bomb calorimetry, and lubricity. Optimum blend ratios of the oxidized fuels in a low sulfur diesel fuel to obtain maximum lubricity are determined.