This paper deals with the peroxide curing of NR. At high temperature and high DCP loading, changes in the crosslinking mechanism were observed. The results confirm that the crosslink efficiency might be >1. Under these conditions both mechanisms, abstraction of an allylic hydrogen and addition to the double bond can take place. H-1 NMR, fracture analysis and tensile stress data reveal that the compound with 3phr DCP crosslinked at 160 degrees C presents a non-uniform distribution of the crosslinks in the network.