The elemental analysis of oils is important for new and used lubricating oils. Wear metals in lubricating oils, such as aluminum, copper, nickel or iron can indicate wear of any oil wetted component and if the level of wear is critical. Other elements like silicon, magnesium or potassium indicate contamination of the oil. The correct addition ofelemen ts, such as molybdenum, calcium, barium, phosphorus and zinc must be monitored. The precision of the analytical results is critical in these cases. Inductively coupled plasma optical emission spectrometry (ICP-OES) due to its multi element capability, large dynamic linear range, stability and low detection limits is accepted and/or suggested in several standard procedures for the analysis of oils [1-10].