Abstract: Data published by the Institute of Materials (IOM) included information on the volatility, sulfur content, and sulfur volatility of 913 engine oils were compiled. These engine oils were collected in three geographic areas -- North America, Europe, and Asia. The volatility data were generated on the Selby-Noack in which all volatilized material is collected for the further analysis of phosphorus and sulfur content. It was found that under the normal Noack test exposure conditions of 250°C for one hour, the Sulfur Emission Index (SEI), a measure of sulfur volatility in mg/L, varied markedly among the engine oils. In a correlation study, minor correlation up to %R2 = 15 was found between sulfur volatility compared to oil volatility and sulfur content of the formulated engine oils. A new concept and application of the Sulfur Volatility Ratio may be useful in explaining observations concerning sulfur volatility dependence.