Magnesium oxide (MgO) nanoparticles were introduced in natural rubber (NR) as an activator to investigate its effect on NR vulcanizates. The MgO nanoparticles were mixed in a ratio of 0-20 p.h.r. before curing at 150ºC. Results of cure time and torque showed that at 12 and 20 p.h.r. loadings, acceptable cure characteristics to that of the control compound, 2 p.h.r. zinc oxide (ZnO) were exhibited. Crosslink density of the vulcanizates, determined by the swelling method confirmed that the MgO nanoparticles intensified the formation of crosslinking. Dispersion of the MgO nanoparticles observed by focused ion-beam/scanning electron microscopy (FIB/SEM) and transmission electron microscopy (TEM) indicated that aggregates of complexes distributed throughout the rubber matrix is consistent with the MgO nanoparticle loadings and were well correlated to the mechanical properties achieved. These findings offer an alternative route for vulcanization formulation of NR.