The paper presents data on the investigation of the conductivity of thin layers (10-7— 10-4m) of mineral oils and hydrocarbons between metal electrodes. Noble and commercial metals (gold, platinum, copper, aluminum) have been used. Part of lubricant conductivity of the contact of rough metal surfaces has been evaluated by computation and testing.Presented as an American Society of Lubrication Engineers paper at the ASME/ASLE Lubrication Conference in San Francisco, California, August 18–21, 1980.