Flame-retardant methyl vinyl silicone rubber (MVMQ)/montmorillonite nanocomposites were prepared by solution intercalation method, using magnesium hydroxide (MH) and red phosphorus (RP) as synergistic flame-retardant additives, and aero silica (SiO2) as synergistic reinforcement filler. The morphologies of the flame-retardant MVMQ/montmorillonite nanocomposites were characterized by environmental scanning electron microscopy (ESEM), and the interlayer spacings were determined by small-angle X-ray scattering (SAXS). In addition to mechanical measurements and limited oxygen index (LOI) test, thermal properties were tested by thermogravimetric anal-ysis (TGA). The decomposition temperature of the nanocomposite that contained 1 wt % montmorillonite can be higher (129 degrees C) than that of MVMQ as basal polymer matrix when 5% weight loss was selected as measuring point. This kind of silicone rubber nanocomposite is a promising flame-retardant polymeric material. (c) 2006 Wiley Periodicals, Inc.