The paper highlights recent situation on the market of motor oils and explains the need for the new generation of motor oil, which is associated with new emission limits EURO IV. Emission limits are obligatory started from 2007. Those emission limits are more stringent than recent Euro III limits in all categories of regulated emissions. New emission limits should contribute to lowering especially particulate matter and nitrogen oxide emissions. That can be accomplished by new types of exhaust aftertreatment, such as SCR catalyst, EGR valve and diesel particulate traps (DPF, CRC). Exhaust aftertreatment with new catalysts and traps also requires a new generation of motor oils. Some of the aftertreatments, especially the PM traps, are very sensitive to some components of motor oils. Effectivity and lifetime of the aftertreatments can thus be largely influence by amount of sulphate ash and by concentration of phosphorus and sulphur in the oils. For a proper function of new aftertreatment catalysts and traps the concentration of the critical elements in the oil had to be lowered. Maximum of the sulphate ash, phosphorus and sulfur contents was established and introduced to each motor oil classifications (API, ACEA, JASO, and OEM classifications). Motor oil meeting the new reduced limits are often referred to as Low SAPS oils. Consequences of reduced content of the critical elements for the oil performance and lifetime are discussed.