Fundamentals of motor oil production, physical-chemical and operational properties, classification of domestic and foreign motor oils, their interchangeability are considered. Recommendations on rational use of engine oils in internal combustion engines are given. Operating conditions of engine oils in the zone of cylinder-piston group of engines, their aging process and influence on various types of wear are considered. Quality and safety requirements for transportation and storage of lubricants are described. For mechanical students. It can be useful for scientific and engineering workers of the automotive industry, specialists and managers of the motor transport complex.