Direct property losses by fires are roughly 0.2% of the gross domestic product and the total costs of fires are around 1% of the gross domestic product. Therefore, it is important to develop well-designed flame retardant materials to decrease both fire risks and fire hazards. Conventional flame retardants like aluminium trihydrate (ATH), magnesium dihydroxide (MDH), organic brominated compounds, or intumescent systems based on nitrogen or phosphorous compounds, sometimes exhibit serious disadvantages. For example, the use of ATH and MDH in flame retardant cables requires a very high loading of these fillers in polymers, which leads to high density and lack of flexibility in end products. Now, a new class of materials, called nanocomposites, has been found to overcome the disadvantages of the traditional flame retardant systems. Generally the term nanocomposite describes a two-phase material with a suitable nanofiller (usually modified layered silicates like montmorillonite (organoclay) or carbon nanotubes) dispersed in the polymer matrix at the nanometer (10-9 m) scale. Compared with pure polymers, the corresponding nanocomposites show tremendous improvements. The content of nanofillers within the polymer matrix is usually between 2 weight-% and 10 weight-%. The most important properties improved by nanocomposites are mechanical properties such as tension, compression, bending, and fracture, barrier properties like permeability, solvent resistance, translucence, and ionic conductivity. Other highly interesting properties exhibited by polymer nanocomposites concern their increased thermal stability and flame retardancy at very low filler levels. The low filler content in nanocomposites for improved thermal stability is highly attractive for the industry because the end products can be made cheaper and easier to process.