Flouroelastomers and silicone rubbers are employed to manufacture static and dynamic seals for automotive applications since they exhibit appropriate physical and chemical properties for the engine performance. Materials for seals are selected according to their compatibility with the environment and fluids involved in the engine operation in order to prevent premature failures and leakages caused by swelling and/or changes in their mechanical properties. Thus, in particular, the use of new fuels and additives in automotive engines requires studies of compatibility with common sealing elastomers to prevent such failures. Currently, Jatropha oil is being used as a renewable source of fuel in diesel engines for electricity production, transport or agricultural mechanization in various countries. It is used either as biodiesel or as straight vegetable oil (SVO) since it has good heating power and provide exhaust gas with almost no sulfur and aromatic polycyclic compounds. However, the compatibility of elastomers with this SVO has not investigated. Hence, in this work, the physical degradation of silicone rubber (VMQ) and fluoroelastomer/Viton® (FKM) with three fuels, namely, straight Jatropha oil (SJO), diesel, and a blend 80%diesel-20%SJO was studied via static immersion tests (670 hr at 24°C) according to the ASTM-D471 method. Changes in mass, volume, tensile and tear resistance and hardness were assessed according to the standard method. Since viscoelasticity is also an important property for the sealing performance of an elastomer, the changes of creep compliance modulus were determined by creep tests. In addition, the changes of surface morphology and topography were evaluated by SEM and optical profilometry, respectively, in order to evidence pitting or cracking caused by degradation. Overall, low degradation was found for both elastomers immersed in SJO, being VMQ the less degraded.