Fine powders of montmorillonite (MMT)/multiwalled carbon nanotube (MWCNT) hybrids have been prepared by simple grinding of MWCNT with MMT in different weight ratios of MMT to MWCNT (10 : 1, 6 : 1, 3 : 1, 1 : 1, and 1 : 3) and characterized by wide-angle X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy. These studies have established the formation of the exfoliated structures of MMT/MWCNT (1 : 1) hybrid, in which MWCNTs exist in the state of single nanotubes that are adsorbed and intercalated on the surface and in between the MMT nanoplatelets. The hybrid has subsequently been used as reinforcing nanofiller in the development of high-performance silicone rubber (SR) nanocomposites, and a remarkably synergistic effect of MMT and MWCNT on SR properties has been observed. The tensile strength of SR containing 1% w/w of the MMT/MWCNT (1 : 1) hybrid is improved by 215%, whereas the SR filled with MMT or MWCNT alone showed an improvement of 46 and 25%, respectively, over that of unfilled SR. In addition, SR/1 wt % MMT/MWCNT (1 : 1) nanocomposites also exhibit the maximum improvement in thermal stability corresponding to 10% weight loss by 70°C, crystallization and melting temperatures increased by 8 and 6°C as inferred from thermogravimetric analysis and differential scanning calorimetry, respectively. This approach is promising for the preparation of high-performance SR nanocomposites by using different dimension nanofillers together. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41818.