Silicone rubber is widely used for electrical insulation structure and it is exposed to harsh environment during its actual service conditions in the power system network. The insulation properties of silicone rubber could be improved by incorporating it with optimized quantity of nanofillers. The silicone rubber nanocomposites are fabricated with the optimized quantity of nanofillers and its insulation characteristics with and without exposure to gamma irradiation are investigated in the present work. The mechanisms governing the improvement in electrical properties as well as characteristic variation in properties of gamma irradiated nanocompostes are discussed.