Stress relaxation in compression in air has been studied for compounds of various polymers. However, rubber seals gaskets, and other applications are widely used where swelling agents such as oil are encountered. It was thought desirable to measure the stress relaxation properties of various rubbers to determine their performance under such conditions. The results show that continous stress relaxation is inhibited by the presence of oil, and that unconfined swelling measurements predict the degree of inhibition directly. The variable of temperature and types of oil were investigated.