The expectations over novel composite materials have been increased especially in automotive and aerospace applications due to its superior weight to strength ratio and tailored mechanical properties. In this frame work, aluminum alloy AA5083 alloy matrix reinforced with micron (10% wt – 5% wt) and nanoparticles (1% wt – 5% wt) of Al2O3.The composite samples were fabricated through powder metallurgy route. Optimum amount of reinforcement were determined by evaluating mechanical properties like micro-hardness and compressive strength of composites. The characterizations were probed by Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD) methods. The results reveal that the composites containing 2% wt of nanoAl2O3and 8 % micro Al2O3reinforcement witnessed superior mechanical properties due to its combined effect of concentration and particulate scale and the great isotropic behavior was achieved by homogenous dispersion of reinforcement in the matrix phase.