The article refers to the common task of lubrication system. The fast development of the world's maritime sector, makes competition among countries increasing. Because of the deterioration of the global economy, the shipping companies, ship-owners want to reduce freight rates, to meet safety requirements, as well as improving conditions of exploitation and operating the machines to prevent the pollution of the marine environment. While exploiting the diesel engine in general and Sulzer diesel engines in particular, ship owners are always eager to reduce the operating cost and still ensure the engine running are safe and reliable. Provide an example of how to calculate the amount of cylinder lubricating oil according to the theory of slow-speed marine engines. The article refers to the costs of the operation and exploitation of ship, offer solution to reduce extraction costs by optimizing the amount of lubricating oil for the cylinders. The analyses in the article are based on Sulzer RTA engines. The article also refers to the level of actual lubrication oil for the cylinders of slow-speed marine engines during operation and exploitation based on the practical experience of the chief engineers, who had ever worked with these engines. The optimal adjustment of cylinder lubricating oil of Sulzer RTA diesel engines to reduce the operating cost but still ensure the engine running are safe and reliable and the problems need to be noted in the process of adjustment.