A lubricating oil re-refining system and process provide a highly efficient and environmentally sound alternative for reclaiming and reusing spent oils. The re-refining process advantageously removes the additives, water, wear metals and other contaminants from the used lubricating oil, while at the same time, returns the base oil fraction that once again can be blended with additives and can be restored to its original high quality specifications for reuse without causing secondary pollution.