Multiwalled carbon nanotubes decorated with nanosilica particles (CS hybrids) were prepared for the first time by ultrasonication assisted mixing of the aqueous dispersions of carboxylated multiwalled carbon nanotubes (MWCNTRs) and colloidal nanosilica. The natural rubber (NR) nanocomposite (NRCSF) was prepared with CS hybrid filler by latex stage mixing method. The SEM and TEM images and strain sweep studies confirmed the formation of segregated network structure inside the nanocomposite due to the alignment of hybrid fillers along the periphery of NR latex spheres. The NRCSF composite exhibited excellent mechanical properties and solvent barrier properties. The NRCSF composites displayed high dielectric constant and low electrical percolation threshold (0.80 vol%). The composite exhibited low dielectric loss because of the presence of insulating nanosilica particles around conducing carbon nanotubes. These elastomeric nanocomposites with high k and low loss are promising in the field of dielectric elastomers for actuator applications.