In this study, Mg based nanocomposite reinforced with nano alumina and graphene nano-platelets as hybrid reinforcement was fabricated by rheo casting followed by hot extrusion at 450 degrees C. Microstructure investigations showed that in comparison with the base alloy, addition of hybrid reinforcement has significant effects on grain refining (up to similar to 44%), decrease of area percent of eutectic phase (up to similar to 38%), evaluation of dynamic precipitations morphology and decrease of basal texture (up to similar to 23%). Mechanical properties results showed that fabricated nanocomposite exhibits simultaneously enhancement of micro-hardness (similar to 33% increase), tensile and compressive yield strengths (similar to 27% and 12% increase, respectively), ultimate tensile and compressive strengths (similar to 33% and 10% increase, respectively), and tensile and compressive fracture strains (similar to 42% and 13% increase, respectively). Simultaneous enhancement of strength and ductility in the nanocomposite introduced this hybrid reinforcement as the new class of reinforcements with higher performance.