This paper presents work specifically designed to study the use of hydrogenated nitrile rubber (HNBR) in the automotive industry. Peroxide cured HNBR compounds were immersed in five standard automotive fluids for periods up to 1500 hours at 135°C and 150°C. The effects on aging behavior of unsaturation level, metal oxides and antioxidants were studied. HNBR is also compared to other heat and oil-resistant elastomers in the same five fluids for a shorter aging period (168 hours at 150°C).The effect of long term heat aging on HNBR compounds with various sulfur cures is also shown in comparison with a peroxide cured compound. In addition, the paper presents data on long term compression set resistance.