The interfacial adhesion between two rubber sheets depends not only on the surface energy but also the degree of physical or chemical crosslinking at interface. It is known that autohesion occurring between elastomer sheets of same type depends on interfacial diffusion and molecular interlocking by either physically or chemically. In case of adhesion of two different rubbers crosslinked at different degrees, it is not well known that what type of bonds and what mechanism of fracture are involved at the interfaces. This paper describes the adhesion behaviors of carbon black-filled elastomer sheets based on ethylene-propylene-diene-termonomer (EPDM) and fluoroelastomer (FKM), where the degree of crosslinking was controlled to figure out the type of interactions involved in the adhesion strength. The adhesion strength was measured by the 180„a peel test. As expected, the adhesive strength Ga was found to increase as the degree of crosslinking of one rubber sheet was controlled to be lower (the degree of crosslinking at the interface will be higher). When the degree of crosslinking of one layer was kept to be minimum (two uncrosslinked rubber sheets), the Ga was approaching to the level of their tearing strength Gc of fully-crosslinked rubber sheet. One interesting observation was that a considerable value of Ga was found even for the fully-crosslinked FKM sheets, which was not observed in the fully-crosslinked EPDM sheets. The abnormal behaviour of FKM sheets seems to responsible for the strong electrostatic attractions between hydrogen and fluorine of the FKM elastomer.