Most EPDM applications require cross-linking, which is commonly achieved via accelerated sulphur vulcanization. Co-agent-assisted peroxide cure is applied for improving the thermal stability and/or the compression set of EPDM. Activated resol cure is only used for the dynamic vulcanization of PP/EPDM blends, i.e. for the production of TPVs. In this paper an overview is given of the chemical structures of the intermediates, the end products and the side products formed upon cross-linking of EPDM. In addition, reaction mechanisms are presented, explaining the various structures formed. (Dis)advantages of the three cross-linking systems are addressed.