Base Lubricants is the name given to lubrication initially produced from refining (mineral base lubricants) or through chemical synthesis (synthetic base lubricants). Base Lubricants is typically defined as oil with a boiling point range between 550 and 1050 F, consisting of hydrocarbons with 18 to 40 carbon atoms. This lubricant can be either paraffinic or napthenic in nature depending on the chemical structure of the molecules.

Almost every lubricant used in plants today started off as just a base Lubricants. The American Petroleum Institute (API) has categorized base lubricants into five categories (API 1509, Appendix E). The first three groups are refined from petroleum. Group IV base lubricants are full synthetic polyalphaolefin. Group V is for all other base lubricants not included in Groups I through IV. Before all the additives are added to the mixture.