Composite polymer materials containing a wide array of particles have provided improvements in non-electrical properties, such as hardness, thermal expansion abrasion resistance, weight and cost. However, when applied as dielectrics, these composites often display some degradation in electrical performance, when compared with their unfilled counterparts. In recent years nanocomposites (i.e., composites with fillers smaller than 100 nm) have been shown to process many of the same improvements without the associated decrease in electrical properties that are improved over unfilled resins. The remarkable changes on these properties of polymers due the addition of inorganic solic nanoparticles is explained by the huge surface area, which increases the interaction between the nanoparticle and the polymer. Moreover, nanocomposites can be produced using conventional polymer processing techniques, which makes them particularly interesting from the production point of view. The topic of my paper: what are the advantages of nanocomposites and what are the differences between unfilled, micro-filled, and nanofilled composites in dielectric properties.