Due to their excellent properties such as high specific stiffness, strength/weight ratio, and wear resistance, metal matrix composites (MMCs) with particulate reinforcement and related manufacturing methods have become important research topics in recent years. Magnesium MMCs are materials that are commonly used for fabrication of light-weight functional components. Magnesium MMCs that are reinforced with various fractions of B4C (3, 6, and 9 wt.%) were fabricated by powder metallurgy (PM) technique using a sintering cycle in a vacuum furnace at 590A degrees C for 9 h. A qualitative analysis of X-ray diffraction (XRD) patterns indicated the formation of Al2O3, MgO, and MgB2 phases in the structure of Mg/B4C MMCs. The sintered density of the MMCs decreased with an increase in the amount of B4C addition. The hardness of the MMCs was found to be higher than that of unreinforced Mg. The compressive test results also showed a significant effect of 3 wt.% B4C content on the compressive strength of magnesium MMCs manufactured by the PM technique.