A process for producing a lubricating base oil having high oxidation stability, wherein the feed used to prepare the lubricating base oil contains at least 5 wt. % olefins, said process comprising (a) determining the weight percent of olefins present in the feed by means of .sup.1H NMR; (b) hydroprocessing the feed under hydroprocessing conditions selected to reduce the amount of olefins present to a target value which has been pre-determined by means of .sup.1H NMR to produce a lubricating base oil having the desired oxidation stability; and (c) collecting a lubricating base oil having the selected oxidation stability from the hydroprocessing zone.