Compression stress relaxation is becoming an increasingly useful tool to determine how well a sealing material will perform in various environments. While stress relaxation data has been published on some rubber materials, there is very little recent data for ethylene/acrylic elastomer, even though it is one viable option for engine and transmission gasket applications. In addition, three new grades of ethylene/acrylic elastomer have been recently commercialized, all of which make very suitable gasket materials. This makes it very timely to investigate the performance of this family of sealing materials.The purpose of this paper is to measure compression stress relaxation for these new grades of ethylene/acrylic in both SG engine oil and automatic transmission fluid for extended periods of time. The results of the ethylene/acrylic grades will also be compared to those of functionally competitive materials, such as polyacrylate and silicone.