Nowadays polymers are used in wide range applications of industries. Parts of the electronic devices composed of polymer materials can be easily ignited because they are susceptible to flame. In this study, it was aimed to produce flame retardant nanocomposite materials by reinforcing halogen-free inorganic additives and to use in components of electronic devices. Within this scope, halogen-free nano sized milled huntite/hydromagnesite and antimony trioxide nanoparticles were reinforced in polymer matrix. The composites reinforced in various ratios were produced using a twin screw extruder. These samples were obtained by the method of injection molding from the extruded granules for the flame retardant test. Structural, morphological, thermal, mechanical and flame retardancy properties of samples were characterized by XRD, SEM, FTIR, DTA-TG, mechanical and flame retardant measurement. It is found that the inorganic reinforcement minerals improved the flame retardant properties and thermal stability of polymer nanocomposites depending on the amount of additives. The huntite/hydromagnesite and antimony trioxide effectively reduce the flammability of the ABS composites utilizing synergism by achieving UL94/V-0 classification.