The oil consumption of an internal combustion engine is a significant performance attribute. The loss of engine oil through the combustion chamber is critical because it impacts the emissions signature of the engine and potentially poisons any exhaust gas after treatment devices. Also the level of oil consumption is an important quality perception to the customer. The engine should not have to require any add oil between oil changes. While developing new engines or solving oil consumption problems on existing engines, it is important to be able to measure the oil consumption of an engine and have confidence in that measurement. The purpose of this document is to review the different measurement methods, outlining their fundamental operating principles, their advantages, and their disadvantages. There is no attempt to identify the best measurement method because the best method will depend on the situation, the objectives, and on capabilities of the organization.