The fluoroelastomer rubber (FR) was successfully incorporated in natural rubber (NR) matrix composites using a colloid stabilization-destabilization methodology in the spherical shape of a few-micrometer size, where the electrostatic surface charge of the FR and NR colloidal drops were controlled to give either stable or unstable colloid mixtures. Measuring the zeta potential of the drops with respect to pH, the stabilized colloid mixture ensured the FR to be incorporated up to 25 phr in the NR matrix as a well-dispersed ocean-island composite structure with the FR size of $0.5{sim}10{mu}m$. The NR/FR composites including various additive fillers showed a good interfacial bonding and enhanced thermal stability with substantially increased mechanical properties of strength as well as elongation- atbreak values. This novel technique provided a unique and highly loaded composite structure composed of FR spherical particles well dispersed in the NR matrix, which can hardly be achieved by the conventional shear-mixing techniques because of the high viscosity and viscoelastic characteristics of elastomers.